diff --git a/codegen/import_build.go b/codegen/import_build.go
index cafbb25396f..657511e93c7 100644
--- a/codegen/import_build.go
+++ b/codegen/import_build.go
@@ -2,6 +2,7 @@ package codegen
 
 import (
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 )
@@ -29,6 +30,8 @@ func buildImports(types NamedTypes, destDir string) Imports {
 	return imports
 }
 
+var invalidPackageNameChar = regexp.MustCompile(`[^\w]`)
+
 func (s Imports) addPkg(types NamedTypes, destDir string, pkg string) (Imports, *Import) {
 	if pkg == "" {
 		return s, nil
@@ -40,11 +43,11 @@ func (s Imports) addPkg(types NamedTypes, destDir string, pkg string) (Imports,
 
 	localName := ""
 	if !strings.HasSuffix(destDir, pkg) {
-		localName = filepath.Base(pkg)
+		localName = invalidPackageNameChar.ReplaceAllLiteralString(filepath.Base(pkg), "_")
 		i := 1
 		imp := s.findByName(localName)
 		for imp != nil && imp.Package != pkg {
-			localName = filepath.Base(pkg) + strconv.Itoa(i)
+			localName = invalidPackageNameChar.ReplaceAllLiteralString(filepath.Base(pkg), "_") + strconv.Itoa(i)
 			imp = s.findByName(localName)
 			i++
 			if i > 10 {
diff --git a/test/generated.go b/test/generated.go
index eff50f80572..c2427e537a4 100644
--- a/test/generated.go
+++ b/test/generated.go
@@ -14,6 +14,7 @@ import (
 	query "github.com/vektah/gqlgen/neelance/query"
 	schema "github.com/vektah/gqlgen/neelance/schema"
 	introspection1 "github.com/vektah/gqlgen/test/introspection"
+	invalid_identifier "github.com/vektah/gqlgen/test/invalid-identifier"
 	models "github.com/vektah/gqlgen/test/models"
 )
 
@@ -29,6 +30,7 @@ type Resolvers interface {
 	Query_recursive(ctx context.Context, input *RecursiveInputSlice) (*bool, error)
 	Query_mapInput(ctx context.Context, input *map[string]interface{}) (*bool, error)
 	Query_collision(ctx context.Context) (*introspection1.It, error)
+	Query_invalidIdentifier(ctx context.Context) (*invalid_identifier.InvalidIdentifier, error)
 }
 
 type executableSchema struct {
@@ -127,6 +129,33 @@ func (ec *executionContext) _InnerObject_id(ctx context.Context, field graphql.C
 	return graphql.MarshalInt(res)
 }
 
+var invalidIdentifierImplementors = []string{"InvalidIdentifier"}
+
+// nolint: gocyclo, errcheck, gas, goconst
+func (ec *executionContext) _InvalidIdentifier(ctx context.Context, sel []query.Selection, obj *invalid_identifier.InvalidIdentifier) graphql.Marshaler {
+	fields := graphql.CollectFields(ec.Doc, sel, invalidIdentifierImplementors, ec.Variables)
+	out := graphql.NewOrderedMap(len(fields))
+	for i, field := range fields {
+		out.Keys[i] = field.Alias
+
+		switch field.Name {
+		case "__typename":
+			out.Values[i] = graphql.MarshalString("InvalidIdentifier")
+		case "id":
+			out.Values[i] = ec._InvalidIdentifier_id(ctx, field, obj)
+		default:
+			panic("unknown field " + strconv.Quote(field.Name))
+		}
+	}
+
+	return out
+}
+
+func (ec *executionContext) _InvalidIdentifier_id(ctx context.Context, field graphql.CollectedField, obj *invalid_identifier.InvalidIdentifier) graphql.Marshaler {
+	res := obj.ID
+	return graphql.MarshalInt(res)
+}
+
 var itImplementors = []string{"It"}
 
 // nolint: gocyclo, errcheck, gas, goconst
@@ -219,6 +248,8 @@ func (ec *executionContext) _Query(ctx context.Context, sel []query.Selection) g
 			out.Values[i] = ec._Query_mapInput(ctx, field)
 		case "collision":
 			out.Values[i] = ec._Query_collision(ctx, field)
+		case "invalidIdentifier":
+			out.Values[i] = ec._Query_invalidIdentifier(ctx, field)
 		case "__schema":
 			out.Values[i] = ec._Query___schema(ctx, field)
 		case "__type":
@@ -433,6 +464,28 @@ func (ec *executionContext) _Query_collision(ctx context.Context, field graphql.
 	})
 }
 
+func (ec *executionContext) _Query_invalidIdentifier(ctx context.Context, field graphql.CollectedField) graphql.Marshaler {
+	return graphql.Defer(func() (ret graphql.Marshaler) {
+		defer func() {
+			if r := recover(); r != nil {
+				userErr := ec.Recover(r)
+				ec.Error(userErr)
+				ret = graphql.Null
+			}
+		}()
+		rctx := graphql.WithResolverContext(ctx, &graphql.ResolverContext{Field: field})
+		res, err := ec.resolvers.Query_invalidIdentifier(rctx)
+		if err != nil {
+			ec.Error(err)
+			return graphql.Null
+		}
+		if res == nil {
+			return graphql.Null
+		}
+		return ec._InvalidIdentifier(ctx, field.Selections, res)
+	})
+}
+
 func (ec *executionContext) _Query___schema(ctx context.Context, field graphql.CollectedField) graphql.Marshaler {
 	res := ec.introspectSchema()
 	if res == nil {
@@ -1139,6 +1192,10 @@ type It {
     id: ID!
 }
 
+type InvalidIdentifier {
+    id: Int!
+}
+
 type Query {
     nestedInputs(input: [[OuterInput]] = [[{inner: {id: 1}}]]): Boolean
     nestedOutputs: [[OuterObject]]
@@ -1146,5 +1203,6 @@ type Query {
     recursive(input: RecursiveInputSlice): Boolean
     mapInput(input: Changes): Boolean
     collision: It
+    invalidIdentifier: InvalidIdentifier
 }
 `)
diff --git a/test/invalid-identifier/invalid-identifier.go b/test/invalid-identifier/invalid-identifier.go
new file mode 100644
index 00000000000..1b13723059b
--- /dev/null
+++ b/test/invalid-identifier/invalid-identifier.go
@@ -0,0 +1,5 @@
+package invalid_identifier
+
+type InvalidIdentifier struct {
+	ID int
+}
diff --git a/test/resolvers_test.go b/test/resolvers_test.go
index 39cdfcca38e..1a8bd226aed 100644
--- a/test/resolvers_test.go
+++ b/test/resolvers_test.go
@@ -14,6 +14,7 @@ import (
 	gqlerrors "github.com/vektah/gqlgen/neelance/errors"
 	"github.com/vektah/gqlgen/neelance/query"
 	"github.com/vektah/gqlgen/test/introspection"
+	invalid_identifier "github.com/vektah/gqlgen/test/invalid-identifier"
 	"github.com/vektah/gqlgen/test/models"
 )
 
@@ -77,12 +78,13 @@ func mkctx(doc *query.Document, errFn func(e error) string) context.Context {
 }
 
 type testResolvers struct {
-	inner            models.InnerObject
-	innerErr         error
-	nestedInputs     *bool
-	nestedInputsErr  error
-	nestedOutputs    [][]models.OuterObject
-	nestedOutputsErr error
+	inner             models.InnerObject
+	innerErr          error
+	nestedInputs      *bool
+	nestedInputsErr   error
+	nestedOutputs     [][]models.OuterObject
+	nestedOutputsErr  error
+	invalidIdentifier *invalid_identifier.InvalidIdentifier
 }
 
 func (r *testResolvers) Query_shapes(ctx context.Context) ([]Shape, error) {
@@ -113,6 +115,10 @@ func (r *testResolvers) Query_nestedOutputs(ctx context.Context) ([][]models.Out
 	return r.nestedOutputs, r.nestedOutputsErr
 }
 
+func (r *testResolvers) Query_invalidIdentifier(ctx context.Context) (*invalid_identifier.InvalidIdentifier, error) {
+	return r.invalidIdentifier, nil
+}
+
 type specialErr struct{}
 
 func (*specialErr) Error() string {
diff --git a/test/schema.graphql b/test/schema.graphql
index 029b976103a..52d9c475a4b 100644
--- a/test/schema.graphql
+++ b/test/schema.graphql
@@ -44,6 +44,10 @@ type It {
     id: ID!
 }
 
+type InvalidIdentifier {
+    id: Int!
+}
+
 type Query {
     nestedInputs(input: [[OuterInput]] = [[{inner: {id: 1}}]]): Boolean
     nestedOutputs: [[OuterObject]]
@@ -51,4 +55,5 @@ type Query {
     recursive(input: RecursiveInputSlice): Boolean
     mapInput(input: Changes): Boolean
     collision: It
+    invalidIdentifier: InvalidIdentifier
 }
diff --git a/test/types.json b/test/types.json
index 358fedf6dd3..58035934ffa 100644
--- a/test/types.json
+++ b/test/types.json
@@ -5,5 +5,6 @@
     "Rectangle": "github.com/vektah/gqlgen/test.Rectangle",
     "RecursiveInputSlice": "github.com/vektah/gqlgen/test.RecursiveInputSlice",
     "It": "github.com/vektah/gqlgen/test/introspection.It",
-    "Changes": "map[string]interface{}"
+    "Changes": "map[string]interface{}",
+    "InvalidIdentifier": "github.com/vektah/gqlgen/test/invalid-identifier.InvalidIdentifier"
 }