diff --git a/package-lock.json b/package-lock.json
index b24ac27..8047747 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -40,7 +40,7 @@
         "postcss-inline-svg": "^6.0.0",
         "postcss-modules": "^6.0.0",
         "prettier": "^2.7.1",
-        "sass": "^1.49.0",
+        "sass": "^1.77.8",
         "string-hash": "^1.1.3",
         "tslib": "^2.4.0",
         "typescript": "^4.7.4",
@@ -7736,9 +7736,9 @@
       "peer": true
     },
     "node_modules/sass": {
-      "version": "1.63.6",
-      "resolved": "https://registry.npmjs.org/sass/-/sass-1.63.6.tgz",
-      "integrity": "sha512-MJuxGMHzaOW7ipp+1KdELtqKbfAWbH7OLIdoSMnVe3EXPMTmxTmlaZDCTsgIpPCs3w99lLo9/zDKkOrJuT5byw==",
+      "version": "1.77.8",
+      "resolved": "https://registry.npmjs.org/sass/-/sass-1.77.8.tgz",
+      "integrity": "sha512-4UHg6prsrycW20fqLGPShtEvo/WyHRVRHwOP4DzkUrObWoWI05QBSfzU71TVB7PFaL104TwNaHpjlWXAZbQiNQ==",
       "dependencies": {
         "chokidar": ">=3.0.0 <4.0.0",
         "immutable": "^4.0.0",
@@ -14559,9 +14559,9 @@
       "peer": true
     },
     "sass": {
-      "version": "1.63.6",
-      "resolved": "https://registry.npmjs.org/sass/-/sass-1.63.6.tgz",
-      "integrity": "sha512-MJuxGMHzaOW7ipp+1KdELtqKbfAWbH7OLIdoSMnVe3EXPMTmxTmlaZDCTsgIpPCs3w99lLo9/zDKkOrJuT5byw==",
+      "version": "1.77.8",
+      "resolved": "https://registry.npmjs.org/sass/-/sass-1.77.8.tgz",
+      "integrity": "sha512-4UHg6prsrycW20fqLGPShtEvo/WyHRVRHwOP4DzkUrObWoWI05QBSfzU71TVB7PFaL104TwNaHpjlWXAZbQiNQ==",
       "requires": {
         "chokidar": ">=3.0.0 <4.0.0",
         "immutable": "^4.0.0",
diff --git a/package.json b/package.json
index a8c9c69..c6e0fa2 100644
--- a/package.json
+++ b/package.json
@@ -52,7 +52,7 @@
     "postcss-inline-svg": "^6.0.0",
     "postcss-modules": "^6.0.0",
     "prettier": "^2.7.1",
-    "sass": "^1.49.0",
+    "sass": "^1.77.8",
     "string-hash": "^1.1.3",
     "tslib": "^2.4.0",
     "typescript": "^4.7.4",
diff --git a/src/build/__tests__/__fixtures__/scss-only/mixed-declarations/styles.scss b/src/build/__tests__/__fixtures__/scss-only/mixed-declarations/styles.scss
new file mode 100644
index 0000000..8789bfd
--- /dev/null
+++ b/src/build/__tests__/__fixtures__/scss-only/mixed-declarations/styles.scss
@@ -0,0 +1,11 @@
+.example {
+  color: red;
+
+  a {
+    font-weight: bold;
+  }
+
+  // top level style after the nested rule to trigger this deprecation warning
+  // https://sass-lang.com/documentation/breaking-changes/mixed-decls/
+  font-weight: normal;
+}
diff --git a/src/build/__tests__/styles.test.ts b/src/build/__tests__/styles.test.ts
index 6ce436c..ffd589e 100644
--- a/src/build/__tests__/styles.test.ts
+++ b/src/build/__tests__/styles.test.ts
@@ -1,16 +1,19 @@
 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 import { expect, test } from 'vitest';
-import { buildStyles, InlineStylesheet } from '../internal';
+import { buildStyles, InlineStylesheet, BuildStylesOptions } from '../internal';
 import { join } from 'node:path';
 import { readFileSync, readdirSync } from 'node:fs';
 
 const fixturesRoot = join(__dirname, '__fixtures__', 'scss-only');
 const outputRoot = join(__dirname, 'out', 'scss-only');
 
-async function buildWithFixtures(suiteName: string, inlines?: InlineStylesheet[]) {
+async function buildWithFixtures(
+  suiteName: string,
+  { inlines, options }: { inlines?: InlineStylesheet[]; options?: BuildStylesOptions } = {}
+) {
   const outDir = join(outputRoot, suiteName);
-  await buildStyles(join(fixturesRoot, suiteName), join(outputRoot, suiteName), inlines);
+  await buildStyles(join(fixturesRoot, suiteName), join(outputRoot, suiteName), inlines, options);
   return outDir;
 }
 
@@ -40,7 +43,9 @@ test('bundles all imports for styles.scss entry point', async () => {
 });
 
 test('supports virtual stylesheets', async () => {
-  const outDir = await buildWithFixtures('inlines', [{ url: 'awsui:tokens', contents: '$color-background: #abcabc' }]);
+  const outDir = await buildWithFixtures('inlines', {
+    inlines: [{ url: 'awsui:tokens', contents: '$color-background: #abcabc' }],
+  });
   expect(readdirSync(outDir)).toEqual(['styles.css.js', 'styles.scoped.css', 'styles.selectors.js']);
   const cssContent = readFileSync(join(outDir, 'styles.scoped.css'), 'utf8');
   expect(cssContent).toContain('#abcabc');
@@ -51,6 +56,16 @@ test('throws an error if a virtual stylesheet is not defined', async () => {
   await expect(() => buildWithFixtures('inlines')).rejects.toThrowError(/awsui:tokens/);
 });
 
+test('ignores deprecation warnings by default', async () => {
+  await expect(buildWithFixtures('mixed-declarations')).resolves.toEqual(expect.any(String));
+});
+
+test('throws an error if errors on deprecation warnings are enabled', async () => {
+  await expect(() =>
+    buildWithFixtures('mixed-declarations', { options: { failOnDeprecations: true } })
+  ).rejects.toThrowError(/Unexpected deprecation warnings during sass build/);
+});
+
 test('mirrors directory structure of the sources', async () => {
   const outDir = await buildWithFixtures('dir-structure');
   expect(readdirSync(outDir)).toEqual(['styles.css.js', 'styles.scoped.css', 'styles.selectors.js', 'sub-component']);
diff --git a/src/build/internal.ts b/src/build/internal.ts
index f643194..62adaa9 100644
--- a/src/build/internal.ts
+++ b/src/build/internal.ts
@@ -1,6 +1,6 @@
 // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
-import { buildStyles, InlineStylesheet } from './tasks/style';
+import { buildStyles, InlineStylesheet, BuildStylesOptions } from './tasks/style';
 import { createPresetFiles } from './tasks/preset';
 import { createInternalTokenFiles } from './tasks/internal-tokens';
 import { createPublicTokenFiles } from './tasks/public-tokens';
@@ -9,7 +9,7 @@ import { getInlineStylesheets } from './inline-stylesheets';
 import { calculatePropertiesMap } from './properties';
 import findNeededTokens from './needed-tokens';
 
-export { buildStyles, InlineStylesheet };
+export { buildStyles, InlineStylesheet, BuildStylesOptions };
 
 export type Tasks = 'preset' | 'design-tokens';
 
@@ -38,6 +38,8 @@ export interface BuildThemedComponentsInternalParams {
   descriptions?: Record<string, string>;
   /** Indicates whether to generate a JSON schema for design tokens JSON format and validate against the schema **/
   jsonSchema?: boolean;
+  /** Fail the build when SASS deprecation warning occurs **/
+  failOnDeprecations?: boolean;
 }
 /**
  * Builds themed components and optionally design tokens, if not skipped.
@@ -68,6 +70,7 @@ export async function buildThemedComponentsInternal(params: BuildThemedComponent
     skip = [],
     descriptions = {},
     jsonSchema = false,
+    failOnDeprecations,
   } = params;
 
   if (!skip.includes('design-tokens') && !designTokensOutputDir) {
@@ -83,7 +86,8 @@ export async function buildThemedComponentsInternal(params: BuildThemedComponent
   const styleTask = buildStyles(
     scssDir,
     componentsOutputDir,
-    getInlineStylesheets(primary, secondary, defaults, variablesMap, propertiesMap, neededTokens)
+    getInlineStylesheets(primary, secondary, defaults, variablesMap, propertiesMap, neededTokens),
+    { failOnDeprecations }
   );
   const internalTokensTask = createInternalTokenFiles(defaults, propertiesMap, componentsOutputDir);
 
diff --git a/src/build/tasks/style.ts b/src/build/tasks/style.ts
index 42e355b..f213dc1 100644
--- a/src/build/tasks/style.ts
+++ b/src/build/tasks/style.ts
@@ -13,9 +13,18 @@ export interface InlineStylesheet {
   contents: string;
 }
 
-export async function buildStyles(sassDir: string, outputDir: string, inlines: InlineStylesheet[] = []) {
+export interface BuildStylesOptions {
+  failOnDeprecations?: boolean;
+}
+
+export async function buildStyles(
+  sassDir: string,
+  outputDir: string,
+  inlines: InlineStylesheet[] = [],
+  options: BuildStylesOptions = {}
+) {
   const files = await promisify(glob)('**/styles.scss', { cwd: sassDir });
-  const compiler = createCompiler(inlines, outputDir, sassDir);
+  const compiler = createCompiler(inlines, outputDir, sassDir, options);
 
   const promises = files.map((file) => compiler(file));
 
@@ -55,15 +64,31 @@ const npmImports = {
   },
 };
 
-function createCompiler(inlines: InlineStylesheet[], outputDir: string, sassDir: string) {
+function createCompiler(inlines: InlineStylesheet[], outputDir: string, sassDir: string, options: BuildStylesOptions) {
   const importer = createImporter(inlines);
   return async (file: string) => {
     const input = path.join(sassDir, file);
+    const deprecations: Array<string> = [];
 
     const sassResult = sass.compile(input, {
+      logger: {
+        warn(message, meta) {
+          if (meta.deprecation && options.failOnDeprecations) {
+            deprecations.push(message);
+          } else {
+            console.warn(message);
+          }
+        },
+      },
       style: 'expanded',
       importers: [importer, npmImports],
     });
+    if (deprecations.length > 0) {
+      for (const deprecation of deprecations) {
+        console.error(deprecation);
+      }
+      throw new Error('Unexpected deprecation warnings during sass build.');
+    }
     const intermediate = path.join(sassDir, rename(file, '.css'));
     const postCSSForEachResult = await postCSSForEach(sassDir, outputDir, sassResult.css, intermediate);
     const postCSSAfterAllResult = await postCSSAfterAll(postCSSForEachResult.css, intermediate);