diff --git a/examples/debug.go b/examples/debug.go
index 2d630925e7a..16e1684dd0a 100644
--- a/examples/debug.go
+++ b/examples/debug.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 )
@@ -22,11 +21,11 @@ func (t *logTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 
 	os.Stdout.Write([]byte("\n[request]\n"))
 	if req.Body != nil {
-		req.Body = ioutil.NopCloser(&readButCopy{req.Body, &buf})
+		req.Body = io.NopCloser(&readButCopy{req.Body, &buf})
 	}
 	req.Write(os.Stdout)
 	if req.Body != nil {
-		req.Body = ioutil.NopCloser(&buf)
+		req.Body = io.NopCloser(&buf)
 	}
 	os.Stdout.Write([]byte("\n[/request]\n"))
 
@@ -40,7 +39,7 @@ func (t *logTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 		res.Body = nil
 		res.Write(os.Stdout)
 		if body != nil {
-			res.Body = ioutil.NopCloser(&echoAsRead{body})
+			res.Body = io.NopCloser(&echoAsRead{body})
 		}
 	}
 
diff --git a/examples/main.go b/examples/main.go
index e60c16bafe2..0a2a2bd2073 100644
--- a/examples/main.go
+++ b/examples/main.go
@@ -11,7 +11,6 @@ import (
 	"flag"
 	"fmt"
 	"hash/fnv"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -198,7 +197,7 @@ func valueOrFileContents(value string, filename string) string {
 	if value != "" {
 		return value
 	}
-	slurp, err := ioutil.ReadFile(filename)
+	slurp, err := os.ReadFile(filename)
 	if err != nil {
 		log.Fatalf("Error reading %q: %v", filename, err)
 	}
diff --git a/google-api-go-generator/clients_test.go b/google-api-go-generator/clients_test.go
index 9a9467e42d1..f8b8105bf08 100644
--- a/google-api-go-generator/clients_test.go
+++ b/google-api-go-generator/clients_test.go
@@ -8,7 +8,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"math"
 	"net/http"
 	"net/http/httptest"
@@ -47,7 +47,7 @@ func (h *myHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	if h.location != "" {
 		w.Header().Set("Location", h.location)
 	}
-	h.body, h.err = ioutil.ReadAll(r.Body)
+	h.body, h.err = io.ReadAll(r.Body)
 	fmt.Fprintf(w, "{}")
 }
 
diff --git a/google-api-go-generator/gen.go b/google-api-go-generator/gen.go
index 33e2ee9eb67..26704bae038 100644
--- a/google-api-go-generator/gen.go
+++ b/google-api-go-generator/gen.go
@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"net/url"
@@ -214,7 +213,7 @@ func getAPIs() []*API {
 			log.Fatalf("-cache=true not compatible with -publiconly=false")
 		}
 		var err error
-		bytes, err = ioutil.ReadFile(apiListFile)
+		bytes, err = os.ReadFile(apiListFile)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -275,7 +274,7 @@ func getAPIsFromFile() []*API {
 }
 
 func apiFromFile(file string) (*API, error) {
-	jsonBytes, err := ioutil.ReadFile(file)
+	jsonBytes, err := os.ReadFile(file)
 	if err != nil {
 		return nil, fmt.Errorf("Error reading %s: %v", file, err)
 	}
@@ -298,7 +297,7 @@ func checkAndUpdateSpecFile(file string, contents []byte) error {
 	if _, err := os.Stat(file); os.IsNotExist(err) {
 		return writeFile(file, contents)
 	}
-	existing, err := ioutil.ReadFile(file)
+	existing, err := os.ReadFile(file)
 	if err != nil {
 		return err
 	}
@@ -329,7 +328,7 @@ func isNewerRevision(old []byte, new []byte) error {
 
 func writeFile(file string, contents []byte) error {
 	// Don't write it if the contents are identical.
-	existing, err := ioutil.ReadFile(file)
+	existing, err := os.ReadFile(file)
 	if err == nil && (bytes.Equal(existing, contents) || basicallyEqual(existing, contents)) {
 		return nil
 	}
@@ -337,7 +336,7 @@ func writeFile(file string, contents []byte) error {
 	if err = os.MkdirAll(outdir, 0755); err != nil {
 		return fmt.Errorf("failed to Mkdir %s: %v", outdir, err)
 	}
-	return ioutil.WriteFile(file, contents, 0644)
+	return os.WriteFile(file, contents, 0644)
 }
 
 var ignoreLines = regexp.MustCompile(`(?m)^\s+"(?:etag|revision)": ".+\n`)
@@ -368,7 +367,7 @@ func slurpURL(urlStr string) []byte {
 		log.Printf("WARNING: URL %s served status code %d", urlStr, res.StatusCode)
 		return nil
 	}
-	bs, err := ioutil.ReadAll(res.Body)
+	bs, err := io.ReadAll(res.Body)
 	if err != nil {
 		log.Fatalf("Error reading body of URL %s: %v", urlStr, err)
 	}
@@ -523,7 +522,7 @@ func (a *API) jsonBytes() []byte {
 		var slurp []byte
 		var err error
 		if *useCache {
-			slurp, err = ioutil.ReadFile(a.JSONFile())
+			slurp, err = os.ReadFile(a.JSONFile())
 			if err != nil {
 				log.Fatal(err)
 			}
diff --git a/google-api-go-generator/gen_test.go b/google-api-go-generator/gen_test.go
index 63a59314bcc..5c598016a55 100644
--- a/google-api-go-generator/gen_test.go
+++ b/google-api-go-generator/gen_test.go
@@ -11,7 +11,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strings"
 	"testing"
@@ -63,17 +63,17 @@ func TestAPIs(t *testing.T) {
 			goldenFile := filepath.Join("testdata", name+".want")
 			if *updateGolden {
 				clean := strings.Replace(string(clean), fmt.Sprintf("gdcl/%s", internal.Version), "gdcl/00000000", -1)
-				if err := ioutil.WriteFile(goldenFile, []byte(clean), 0644); err != nil {
+				if err := os.WriteFile(goldenFile, []byte(clean), 0644); err != nil {
 					t.Fatal(err)
 				}
 			}
-			want, err := ioutil.ReadFile(goldenFile)
+			want, err := os.ReadFile(goldenFile)
 			if err != nil {
 				t.Fatal(err)
 			}
 			wantStr := strings.Replace(string(want), "gdcl/00000000", fmt.Sprintf("gdcl/%s", internal.Version), -1)
 			if !bytes.Equal([]byte(wantStr), clean) {
-				tf, _ := ioutil.TempFile("", "api-"+name+"-got-json.")
+				tf, _ := os.CreateTemp("", "api-"+name+"-got-json.")
 				if _, err := tf.Write(clean); err != nil {
 					t.Fatal(err)
 				}
@@ -219,13 +219,13 @@ func TestSupportsPaging(t *testing.T) {
 
 func TestIsNewerRevision(t *testing.T) {
 	olderBytesPath, newerBytesPath := filepath.Join("testdata", "rev20200415.json"), filepath.Join("testdata", "rev20200416.json")
-	olderBytes, err := ioutil.ReadFile(olderBytesPath)
+	olderBytes, err := os.ReadFile(olderBytesPath)
 	if err != nil {
-		t.Fatalf("ioutil.ReadFile(%q) = %v; want nil", olderBytesPath, err)
+		t.Fatalf("os.ReadFile(%q) = %v; want nil", olderBytesPath, err)
 	}
-	newerBytes, err := ioutil.ReadFile(newerBytesPath)
+	newerBytes, err := os.ReadFile(newerBytesPath)
 	if err != nil {
-		t.Fatalf("ioutil.ReadFile(%q) = %v; want nil", newerBytesPath, err)
+		t.Fatalf("os.ReadFile(%q) = %v; want nil", newerBytesPath, err)
 	}
 
 	// newBytes > oldBytes
diff --git a/google-api-go-generator/internal/disco/disco_test.go b/google-api-go-generator/internal/disco/disco_test.go
index d4ae90e6a62..287b2cc520b 100644
--- a/google-api-go-generator/internal/disco/disco_test.go
+++ b/google-api-go-generator/internal/disco/disco_test.go
@@ -5,7 +5,7 @@
 package disco
 
 import (
-	"io/ioutil"
+	"os"
 	"reflect"
 	"strings"
 	"testing"
@@ -17,7 +17,7 @@ var stringSchema = &Schema{
 }
 
 func TestDocument(t *testing.T) {
-	bytes, err := ioutil.ReadFile("testdata/test-api.json")
+	bytes, err := os.ReadFile("testdata/test-api.json")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -265,7 +265,7 @@ func TestSchemaErrors(t *testing.T) {
 }
 
 func TestErrorDoc(t *testing.T) {
-	bytes, err := ioutil.ReadFile("testdata/error.json")
+	bytes, err := os.ReadFile("testdata/error.json")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/googleapi/googleapi.go b/googleapi/googleapi.go
index b328a7976ab..b5e38c66282 100644
--- a/googleapi/googleapi.go
+++ b/googleapi/googleapi.go
@@ -11,7 +11,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
@@ -144,7 +143,7 @@ func CheckResponse(res *http.Response) error {
 	if res.StatusCode >= 200 && res.StatusCode <= 299 {
 		return nil
 	}
-	slurp, err := ioutil.ReadAll(res.Body)
+	slurp, err := io.ReadAll(res.Body)
 	if err == nil {
 		jerr := new(errorReply)
 		err = json.Unmarshal(slurp, jerr)
@@ -184,7 +183,7 @@ func CheckMediaResponse(res *http.Response) error {
 	if res.StatusCode >= 200 && res.StatusCode <= 299 {
 		return nil
 	}
-	slurp, _ := ioutil.ReadAll(io.LimitReader(res.Body, 1<<20))
+	slurp, _ := io.ReadAll(io.LimitReader(res.Body, 1<<20))
 	return &Error{
 		Code:   res.StatusCode,
 		Body:   string(slurp),
diff --git a/googleapi/googleapi_test.go b/googleapi/googleapi_test.go
index 510a5842630..db06aa273ee 100644
--- a/googleapi/googleapi_test.go
+++ b/googleapi/googleapi_test.go
@@ -6,7 +6,7 @@ package googleapi
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"reflect"
@@ -318,7 +318,7 @@ func TestCheckResponse(t *testing.T) {
 	for _, test := range checkResponseTests {
 		res := test.in
 		if test.bodyText != "" {
-			res.Body = ioutil.NopCloser(strings.NewReader(test.bodyText))
+			res.Body = io.NopCloser(strings.NewReader(test.bodyText))
 		}
 		g := CheckResponse(res)
 		if !reflect.DeepEqual(g, test.want) {
diff --git a/header_test.go b/header_test.go
index 5881762081c..a493d25027a 100644
--- a/header_test.go
+++ b/header_test.go
@@ -6,7 +6,6 @@ package api
 
 import (
 	"bytes"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -43,7 +42,7 @@ func TestLicense(t *testing.T) {
 			return nil
 		}
 
-		src, err := ioutil.ReadFile(path)
+		src, err := os.ReadFile(path)
 		if err != nil {
 			return nil
 		}
diff --git a/idtoken/validate_test.go b/idtoken/validate_test.go
index 631c82e88dc..46528db2747 100644
--- a/idtoken/validate_test.go
+++ b/idtoken/validate_test.go
@@ -14,7 +14,7 @@ import (
 	"crypto/rsa"
 	"encoding/base64"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"math/big"
 	"net/http"
 	"testing"
@@ -97,7 +97,7 @@ func TestValidateRS256(t *testing.T) {
 					}
 					return &http.Response{
 						StatusCode: 200,
-						Body:       ioutil.NopCloser(bytes.NewReader(b)),
+						Body:       io.NopCloser(bytes.NewReader(b)),
 						Header:     make(http.Header),
 					}
 				}),
@@ -207,7 +207,7 @@ func TestValidateES256(t *testing.T) {
 					}
 					return &http.Response{
 						StatusCode: 200,
-						Body:       ioutil.NopCloser(bytes.NewReader(b)),
+						Body:       io.NopCloser(bytes.NewReader(b)),
 						Header:     make(http.Header),
 					}
 				}),
diff --git a/impersonate/idtoken.go b/impersonate/idtoken.go
index a2defff1518..9000b8e0f61 100644
--- a/impersonate/idtoken.go
+++ b/impersonate/idtoken.go
@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"time"
 
@@ -109,7 +108,7 @@ func (i impersonatedIDTokenSource) Token() (*oauth2.Token, error) {
 		return nil, fmt.Errorf("impersonate: unable to generate ID token: %v", err)
 	}
 	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
 	if err != nil {
 		return nil, fmt.Errorf("impersonate: unable to read body: %v", err)
 	}
diff --git a/impersonate/idtoken_test.go b/impersonate/idtoken_test.go
index 4a961822bdf..45d4305a90b 100644
--- a/impersonate/idtoken_test.go
+++ b/impersonate/idtoken_test.go
@@ -8,7 +8,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"testing"
 
@@ -56,7 +56,7 @@ func TestIDTokenSource(t *testing.T) {
 					}
 					return &http.Response{
 						StatusCode: 200,
-						Body:       ioutil.NopCloser(bytes.NewReader(b)),
+						Body:       io.NopCloser(bytes.NewReader(b)),
 						Header:     make(http.Header),
 					}
 				}),
diff --git a/impersonate/impersonate.go b/impersonate/impersonate.go
index 52c32589b72..86d5eb82d58 100644
--- a/impersonate/impersonate.go
+++ b/impersonate/impersonate.go
@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"time"
 
@@ -161,7 +160,7 @@ func (i impersonatedTokenSource) Token() (*oauth2.Token, error) {
 		return nil, fmt.Errorf("impersonate: unable to generate access token: %v", err)
 	}
 	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
 	if err != nil {
 		return nil, fmt.Errorf("impersonate: unable to read body: %v", err)
 	}
diff --git a/impersonate/impersonate_test.go b/impersonate/impersonate_test.go
index c26c7fafc1a..8e6a09ac9a2 100644
--- a/impersonate/impersonate_test.go
+++ b/impersonate/impersonate_test.go
@@ -8,7 +8,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -67,7 +67,7 @@ func TestTokenSource_serviceAccount(t *testing.T) {
 						}
 						return &http.Response{
 							StatusCode: 200,
-							Body:       ioutil.NopCloser(bytes.NewReader(b)),
+							Body:       io.NopCloser(bytes.NewReader(b)),
 							Header:     http.Header{},
 						}
 					}
diff --git a/impersonate/user.go b/impersonate/user.go
index 059deab7117..c234abb8998 100644
--- a/impersonate/user.go
+++ b/impersonate/user.go
@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
@@ -123,7 +122,7 @@ func (u userTokenSource) signJWT() (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("impersonate: unable to sign JWT: %v", err)
 	}
-	body, err := ioutil.ReadAll(io.LimitReader(rawResp.Body, 1<<20))
+	body, err := io.ReadAll(io.LimitReader(rawResp.Body, 1<<20))
 	if err != nil {
 		return "", fmt.Errorf("impersonate: unable to read body: %v", err)
 	}
@@ -148,7 +147,7 @@ func (u userTokenSource) exchangeToken(signedJWT string) (*oauth2.Token, error)
 	if err != nil {
 		return nil, fmt.Errorf("impersonate: unable to exchange token: %v", err)
 	}
-	body, err := ioutil.ReadAll(io.LimitReader(rawResp.Body, 1<<20))
+	body, err := io.ReadAll(io.LimitReader(rawResp.Body, 1<<20))
 	if err != nil {
 		return nil, fmt.Errorf("impersonate: unable to read body: %v", err)
 	}
diff --git a/impersonate/user_test.go b/impersonate/user_test.go
index 0358eecc883..54ec3068d3a 100644
--- a/impersonate/user_test.go
+++ b/impersonate/user_test.go
@@ -8,7 +8,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -69,7 +69,7 @@ func TestTokenSource_user(t *testing.T) {
 						}
 						return &http.Response{
 							StatusCode: 200,
-							Body:       ioutil.NopCloser(bytes.NewReader(b)),
+							Body:       io.NopCloser(bytes.NewReader(b)),
 							Header:     make(http.Header),
 						}
 					}
@@ -85,7 +85,7 @@ func TestTokenSource_user(t *testing.T) {
 						}
 						return &http.Response{
 							StatusCode: 200,
-							Body:       ioutil.NopCloser(bytes.NewReader(b)),
+							Body:       io.NopCloser(bytes.NewReader(b)),
 							Header:     make(http.Header),
 						}
 					}
diff --git a/integration-tests/byoid/integration_test.go b/integration-tests/byoid/integration_test.go
index 612cf8eae4c..e0051c470d9 100644
--- a/integration-tests/byoid/integration_test.go
+++ b/integration-tests/byoid/integration_test.go
@@ -33,7 +33,7 @@ import (
 	"encoding/xml"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
@@ -148,7 +148,7 @@ func writeConfig(t *testing.T, c config, f func(name string)) {
 	t.Helper()
 
 	// Set up config file.
-	configFile, err := ioutil.TempFile("", "config.json")
+	configFile, err := os.CreateTemp("", "config.json")
 	if err != nil {
 		t.Fatalf("Error creating config file: %v", err)
 	}
@@ -223,7 +223,7 @@ func TestFileBasedCredentials(t *testing.T) {
 		t.Skip("skipping integration test")
 	}
 	// Set up Token as a file
-	tokenFile, err := ioutil.TempFile("", "token.txt")
+	tokenFile, err := os.CreateTemp("", "token.txt")
 	if err != nil {
 		t.Fatalf("Error creating token file:")
 	}
@@ -313,7 +313,7 @@ func TestAWSBasedCredentials(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Failed to post data to AWS: %v", err)
 	}
-	bodyBytes, err := ioutil.ReadAll(resp.Body)
+	bodyBytes, err := io.ReadAll(resp.Body)
 	if err != nil {
 		t.Fatalf("Failed to parse response body from AWS: %v", err)
 	}
@@ -369,7 +369,7 @@ func TestExecutableBasedCredentials(t *testing.T) {
 	}
 
 	// Set up Script as a executable file
-	scriptFile, err := ioutil.TempFile("", "script.sh")
+	scriptFile, err := os.CreateTemp("", "script.sh")
 	if err != nil {
 		t.Fatalf("Error creating token file:")
 	}
@@ -402,7 +402,7 @@ func TestConfigurableTokenLifetime(t *testing.T) {
 	}
 
 	// Set up Token as a file
-	tokenFile, err := ioutil.TempFile("", "token.txt")
+	tokenFile, err := os.CreateTemp("", "token.txt")
 	if err != nil {
 		t.Fatalf("Error creating token file:")
 	}
@@ -427,7 +427,7 @@ func TestConfigurableTokenLifetime(t *testing.T) {
 			File: tokenFile.Name(),
 		},
 	}, func(filename string) {
-		b, err := ioutil.ReadFile(filename)
+		b, err := os.ReadFile(filename)
 		if err != nil {
 			t.Fatalf("Coudn't read temp config file")
 		}
diff --git a/integration-tests/downscope/downscope_test.go b/integration-tests/downscope/downscope_test.go
index 25553c9c2d7..12ed93d2735 100644
--- a/integration-tests/downscope/downscope_test.go
+++ b/integration-tests/downscope/downscope_test.go
@@ -8,7 +8,7 @@ import (
 	"context"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"testing"
@@ -137,9 +137,9 @@ func downscopeQuery(t *testing.T, tt downscopeTest) error {
 		return fmt.Errorf("failed to retrieve object from GCP project with error: %v", err)
 	}
 	defer resp.Body.Close()
-	_, err = ioutil.ReadAll(resp.Body)
+	_, err = io.ReadAll(resp.Body)
 	if err != nil {
-		return fmt.Errorf("ioutil.ReadAll: %v", err)
+		return fmt.Errorf("io.ReadAll: %v", err)
 	}
 	return nil
 }
diff --git a/internal/cert/secureconnect_cert.go b/internal/cert/secureconnect_cert.go
index 5913cab8017..afd79ffe2be 100644
--- a/internal/cert/secureconnect_cert.go
+++ b/internal/cert/secureconnect_cert.go
@@ -18,7 +18,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/user"
@@ -59,7 +58,7 @@ func NewSecureConnectSource(configFilePath string) (Source, error) {
 		configFilePath = filepath.Join(user.HomeDir, metadataPath, metadataFile)
 	}
 
-	file, err := ioutil.ReadFile(configFilePath)
+	file, err := os.ReadFile(configFilePath)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			// Config file missing means Secure Connect is not supported.
diff --git a/internal/creds.go b/internal/creds.go
index fd89a2785fd..92b3acf6edf 100644
--- a/internal/creds.go
+++ b/internal/creds.go
@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
@@ -48,7 +47,7 @@ func baseCreds(ctx context.Context, ds *DialSettings) (*google.Credentials, erro
 		return credentialsFromJSON(ctx, ds.CredentialsJSON, ds)
 	}
 	if ds.CredentialsFile != "" {
-		data, err := ioutil.ReadFile(ds.CredentialsFile)
+		data, err := os.ReadFile(ds.CredentialsFile)
 		if err != nil {
 			return nil, fmt.Errorf("cannot read credentials file: %v", err)
 		}
diff --git a/internal/ecp/test_signer.go b/internal/ecp/test_signer.go
index 38425cf677b..4fb41ea98e4 100644
--- a/internal/ecp/test_signer.go
+++ b/internal/ecp/test_signer.go
@@ -11,7 +11,6 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/rpc"
 	"os"
@@ -73,7 +72,7 @@ func (k *EnterpriseCertSigner) Sign(args SignArgs, resp *[]byte) (err error) {
 func main() {
 	enterpriseCertSigner := new(EnterpriseCertSigner)
 
-	data, err := ioutil.ReadFile(os.Args[1])
+	data, err := os.ReadFile(os.Args[1])
 	if err != nil {
 		log.Fatalf("Error reading certificate: %v", err)
 	}
diff --git a/internal/gensupport/buffer_test.go b/internal/gensupport/buffer_test.go
index df5eedb8ff0..8a99744bfbe 100644
--- a/internal/gensupport/buffer_test.go
+++ b/internal/gensupport/buffer_test.go
@@ -7,7 +7,6 @@ package gensupport
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 	"reflect"
 	"testing"
 	"testing/iotest"
@@ -19,7 +18,7 @@ import (
 func getChunkAsString(t *testing.T, mb *MediaBuffer) (string, error) {
 	chunk, _, size, err := mb.Chunk()
 
-	buf, e := ioutil.ReadAll(chunk)
+	buf, e := io.ReadAll(chunk)
 	if e != nil {
 		t.Fatalf("Failed reading chunk: %v", e)
 	}
@@ -250,7 +249,7 @@ func TestAdapter(t *testing.T) {
 		if typer, ok := to.(googleapi.ContentTyper); ok && typer.ContentType() != "ctype" {
 			t.Errorf("content type: got: %s; want: ctype", typer.ContentType())
 		}
-		buf, err := ioutil.ReadAll(to)
+		buf, err := io.ReadAll(to)
 		if err != nil {
 			t.Errorf("error reading data: %v", err)
 			return
diff --git a/internal/gensupport/media.go b/internal/gensupport/media.go
index 8356e7f27b0..c048a57084b 100644
--- a/internal/gensupport/media.go
+++ b/internal/gensupport/media.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net/http"
@@ -222,8 +221,8 @@ func (mi *MediaInfo) UploadRequest(reqHeaders http.Header, body io.Reader) (newB
 		toCleanup = append(toCleanup, combined)
 		if fb != nil && fm != nil {
 			getBody = func() (io.ReadCloser, error) {
-				rb := ioutil.NopCloser(fb())
-				rm := ioutil.NopCloser(fm())
+				rb := io.NopCloser(fb())
+				rm := io.NopCloser(fm())
 				var mimeBoundary string
 				if _, params, err := mime.ParseMediaType(ctype); err == nil {
 					mimeBoundary = params["boundary"]
@@ -243,7 +242,7 @@ func (mi *MediaInfo) UploadRequest(reqHeaders http.Header, body io.Reader) (newB
 		fb := readerFunc(body)
 		if fb != nil {
 			getBody = func() (io.ReadCloser, error) {
-				rb := ioutil.NopCloser(fb())
+				rb := io.NopCloser(fb())
 				toCleanup = append(toCleanup, rb)
 				return rb, nil
 			}
diff --git a/internal/gensupport/media_test.go b/internal/gensupport/media_test.go
index 0ba367b4469..65fd62b3dcc 100644
--- a/internal/gensupport/media_test.go
+++ b/internal/gensupport/media_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	cryptorand "crypto/rand"
 	"io"
-	"io/ioutil"
 	mathrand "math/rand"
 	"net/http"
 	"strings"
@@ -197,7 +196,7 @@ func TestUploadRequestGetBody(t *testing.T) {
 		if getBody == nil {
 			continue
 		}
-		want, err := ioutil.ReadAll(r)
+		want, err := io.ReadAll(r)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -206,7 +205,7 @@ func TestUploadRequestGetBody(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			got, err := ioutil.ReadAll(rc)
+			got, err := io.ReadAll(rc)
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/internal/gensupport/resumable_test.go b/internal/gensupport/resumable_test.go
index 3d6bc068bab..0000d403e0c 100644
--- a/internal/gensupport/resumable_test.go
+++ b/internal/gensupport/resumable_test.go
@@ -8,7 +8,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"reflect"
 	"strings"
@@ -75,7 +74,7 @@ func (t *interruptibleTransport) RoundTrip(req *http.Request) (*http.Response, e
 	}
 
 	if ev.responseStatus != http.StatusServiceUnavailable {
-		buf, err := ioutil.ReadAll(req.Body)
+		buf, err := io.ReadAll(req.Body)
 		if err != nil {
 			return nil, fmt.Errorf("error reading from request data: %v", err)
 		}
diff --git a/internal/impersonate/impersonate.go b/internal/impersonate/impersonate.go
index b465bbcd12e..4b2c775f210 100644
--- a/internal/impersonate/impersonate.go
+++ b/internal/impersonate/impersonate.go
@@ -11,7 +11,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"time"
 
@@ -105,7 +104,7 @@ func (i impersonatedTokenSource) Token() (*oauth2.Token, error) {
 		return nil, fmt.Errorf("impersonate: unable to generate access token: %v", err)
 	}
 	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
 	if err != nil {
 		return nil, fmt.Errorf("impersonate: unable to read body: %v", err)
 	}