diff --git a/scripts/generate-clients/.gitignore b/scripts/generate-clients/.gitignore
index 765a0ca99f962..63a2baf3974b6 100644
--- a/scripts/generate-clients/.gitignore
+++ b/scripts/generate-clients/.gitignore
@@ -1 +1,2 @@
-.aws-models/
\ No newline at end of file
+.aws-models/
+.sdk-codegen/
\ No newline at end of file
diff --git a/scripts/generate-clients/code-gen-dir.js b/scripts/generate-clients/code-gen-dir.js
index 64bee1ab19722..a6d48780d66e5 100644
--- a/scripts/generate-clients/code-gen-dir.js
+++ b/scripts/generate-clients/code-gen-dir.js
@@ -15,6 +15,7 @@ const getCodeGenOutputDir = (dir) =>
 const CODE_GEN_PROTOCOL_TESTS_OUTPUT_DIR = getCodeGenOutputDir("protocol-test-codegen");
 const CODE_GEN_GENERIC_CLIENT_OUTPUT_DIR = getCodeGenOutputDir("generic-client-test-codegen");
 const CODE_GEN_SDK_OUTPUT_DIR = getCodeGenOutputDir("sdk-codegen");
+const TEMP_CODE_GEN_SDK_OUTPUT_DIR = normalize(join(__dirname, ".sdk-codegen"));
 
 module.exports = {
   CODE_GEN_ROOT,
@@ -25,4 +26,5 @@ module.exports = {
   CODE_GEN_GENERIC_CLIENT_OUTPUT_DIR,
   DEFAULT_CODE_GEN_INPUT_DIR,
   TEMP_CODE_GEN_INPUT_DIR,
+  TEMP_CODE_GEN_SDK_OUTPUT_DIR,
 };
diff --git a/scripts/generate-clients/code-gen.js b/scripts/generate-clients/code-gen.js
index eed25153d4275..da0577c9cf878 100644
--- a/scripts/generate-clients/code-gen.js
+++ b/scripts/generate-clients/code-gen.js
@@ -1,9 +1,15 @@
 // @ts-check
 const { basename, join, relative } = require("path");
-const { emptyDirSync } = require("fs-extra");
+const { copySync, emptyDirSync } = require("fs-extra");
 const { copyFileSync } = require("fs");
 const { spawnProcess } = require("../utils/spawn-process");
-const { CODE_GEN_ROOT, CODE_GEN_SDK_ROOT, TEMP_CODE_GEN_INPUT_DIR } = require("./code-gen-dir");
+const {
+  CODE_GEN_ROOT,
+  CODE_GEN_SDK_ROOT,
+  CODE_GEN_SDK_OUTPUT_DIR,
+  TEMP_CODE_GEN_INPUT_DIR,
+  TEMP_CODE_GEN_SDK_OUTPUT_DIR,
+} = require("./code-gen-dir");
 const { getModelFilepaths } = require("./get-model-filepaths");
 
 const generateClients = async (models, batchSize) => {
@@ -22,7 +28,13 @@ const generateClients = async (models, batchSize) => {
       copyFileSync(filepath, join(TEMP_CODE_GEN_INPUT_DIR, filename));
     }
     await spawnProcess("./gradlew", options, { cwd: CODE_GEN_ROOT });
+    // We're copying generated code to temporary directory as it's cleans
+    // codegen directory in every run.
+    // Refs: https://github.com/aws/aws-sdk-js-v3/issues/3321
+    copySync(CODE_GEN_SDK_OUTPUT_DIR, TEMP_CODE_GEN_SDK_OUTPUT_DIR);
   }
+  copySync(TEMP_CODE_GEN_SDK_OUTPUT_DIR, CODE_GEN_SDK_OUTPUT_DIR);
+  emptyDirSync(TEMP_CODE_GEN_SDK_OUTPUT_DIR);
 };
 
 const generateProtocolTests = async () => {