diff --git a/smithy-aws-apigateway-openapi/src/main/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizers.java b/smithy-aws-apigateway-openapi/src/main/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizers.java
index 1e38ca684b0..021fc7f8d2b 100644
--- a/smithy-aws-apigateway-openapi/src/main/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizers.java
+++ b/smithy-aws-apigateway-openapi/src/main/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizers.java
@@ -17,6 +17,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.logging.Logger;
 import software.amazon.smithy.aws.traits.apigateway.AuthorizerDefinition;
 import software.amazon.smithy.aws.traits.apigateway.AuthorizerIndex;
@@ -24,6 +25,7 @@
 import software.amazon.smithy.aws.traits.apigateway.AuthorizersTrait;
 import software.amazon.smithy.model.node.Node;
 import software.amazon.smithy.model.node.ObjectNode;
+import software.amazon.smithy.model.shapes.OperationShape;
 import software.amazon.smithy.model.shapes.ServiceShape;
 import software.amazon.smithy.model.shapes.Shape;
 import software.amazon.smithy.openapi.fromsmithy.Context;
@@ -32,7 +34,9 @@
 import software.amazon.smithy.openapi.fromsmithy.mappers.RemoveUnusedComponents;
 import software.amazon.smithy.openapi.model.ComponentsObject;
 import software.amazon.smithy.openapi.model.OpenApi;
+import software.amazon.smithy.openapi.model.OperationObject;
 import software.amazon.smithy.openapi.model.SecurityScheme;
+import software.amazon.smithy.utils.ListUtils;
 import software.amazon.smithy.utils.MapUtils;
 
 /**
@@ -79,6 +83,25 @@ public Map<String, List<String>> updateSecurity(
                 .orElse(requirement);
     }
 
+    @Override
+    public OperationObject updateOperation(Context context, OperationShape shape, OperationObject operation) {
+        ServiceShape service = context.getService();
+        AuthorizerIndex authorizerIndex = context.getModel().getKnowledge(AuthorizerIndex.class);
+
+        // Get the resolved security schemes of the service and operation, and
+        // only add security if it's different than the service.
+        String serviceAuth = authorizerIndex.getAuthorizer(service).orElse(null);
+        String operationAuth = authorizerIndex.getAuthorizer(service, shape).orElse(null);
+
+        if (operationAuth == null || Objects.equals(operationAuth, serviceAuth)) {
+            return operation;
+        }
+
+        return operation.toBuilder()
+                .addSecurity(MapUtils.of(operationAuth, ListUtils.of()))
+                .build();
+    }
+
     @Override
     public OpenApi after(Context context, OpenApi openapi) {
         return context.getService().getTrait(AuthorizersTrait.class)
diff --git a/smithy-aws-apigateway-openapi/src/test/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizersTest.java b/smithy-aws-apigateway-openapi/src/test/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizersTest.java
index fe695a8c8d0..128b1167dc6 100644
--- a/smithy-aws-apigateway-openapi/src/test/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizersTest.java
+++ b/smithy-aws-apigateway-openapi/src/test/java/software/amazon/smithy/aws/apigateway/openapi/AddAuthorizersTest.java
@@ -16,10 +16,14 @@
 package software.amazon.smithy.aws.apigateway.openapi;
 
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.nullValue;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 
+import java.util.Optional;
 import org.junit.jupiter.api.Test;
 import software.amazon.smithy.model.Model;
 import software.amazon.smithy.model.node.Node;
@@ -28,6 +32,8 @@
 import software.amazon.smithy.openapi.fromsmithy.OpenApiConverter;
 import software.amazon.smithy.openapi.model.OpenApi;
 import software.amazon.smithy.openapi.model.SecurityScheme;
+import software.amazon.smithy.utils.ListUtils;
+import software.amazon.smithy.utils.MapUtils;
 
 public class AddAuthorizersTest {
     @Test
@@ -95,4 +101,26 @@ public void addsCustomAuthType() {
         assertThat(sigV4.getExtension("x-amazon-apigateway-authtype").get(), equalTo(Node.from("myCustomType")));
         assertFalse(sigV4.getExtension("x-amazon-apigateway-authorizer").isPresent());
     }
+
+    @Test
+    public void resolvesEffectiveAuthorizersForEachOperation() {
+        Model model = Model.assembler()
+                .discoverModels(getClass().getClassLoader())
+                .addImport(getClass().getResource("effective-authorizers.smithy"))
+                .assemble()
+                .unwrap();
+        OpenApi result = OpenApiConverter.create()
+                .classLoader(getClass().getClassLoader())
+                .convert(model, ShapeId.from("smithy.example#ServiceA"));
+
+        // The security of the service is just "foo".
+        assertThat(result.getSecurity(), contains(MapUtils.of("foo", ListUtils.of())));
+        // The "baz" and "foo" securitySchemes must be present.
+        assertThat(result.getComponents().getSecuritySchemes().keySet(), containsInAnyOrder("baz", "foo"));
+        // The security schemes of operationA must be empty.
+        assertThat(result.getPaths().get("/operationA").getGet().get().getSecurity(), is(Optional.empty()));
+        // The security schemes of operationB must be "baz".
+        assertThat(result.getPaths().get("/operationB").getGet().get().getSecurity(),
+                   is(Optional.of(ListUtils.of(MapUtils.of("baz", ListUtils.of())))));
+    }
 }
diff --git a/smithy-aws-apigateway-openapi/src/test/resources/software/amazon/smithy/aws/apigateway/openapi/effective-authorizers.smithy b/smithy-aws-apigateway-openapi/src/test/resources/software/amazon/smithy/aws/apigateway/openapi/effective-authorizers.smithy
new file mode 100644
index 00000000000..6ce06635721
--- /dev/null
+++ b/smithy-aws-apigateway-openapi/src/test/resources/software/amazon/smithy/aws/apigateway/openapi/effective-authorizers.smithy
@@ -0,0 +1,20 @@
+namespace smithy.example
+
+@protocols([{name: "aws.rest-json-1.1", auth: ["aws.v4"]}])
+@aws.apigateway#authorizer("foo")
+@aws.apigateway#authorizers(
+    foo: {scheme: "aws.v4", type: "aws", uri: "arn:foo"},
+    baz: {scheme: "aws.v4", type: "aws", uri: "arn:baz"})
+service ServiceA {
+  version: "2019-06-17",
+  operations: [OperationA, OperationB]
+}
+
+// Inherits the authorizer of ServiceA
+@http(method: "GET", uri: "/operationA")
+operation OperationA {}
+
+// Overrides the authorizer of ServiceA
+@aws.apigateway#authorizer("baz")
+@http(method: "GET", uri: "/operationB")
+operation OperationB {}