diff --git a/packages/angular/cli/lib/config/schema.json b/packages/angular/cli/lib/config/schema.json
index d2a5a6c3d0b8..cb1bfc431689 100644
--- a/packages/angular/cli/lib/config/schema.json
+++ b/packages/angular/cli/lib/config/schema.json
@@ -376,17 +376,57 @@
           "type": "object",
           "properties": {
             "sourceLocale": {
-              "type": "string",
-              "description": "Specifies the source language of the application.",
-              "default": "en-US"
+              "oneOf": [
+                {
+                  "type": "string",
+                  "description": "Specifies the source locale of the application.",
+                  "default": "en-US",
+                  "pattern": "^[a-z]{2}(-[a-zA-Z]{2,})?$"
+                },
+                {
+                  "type": "object",
+                  "description": "Localization options to use for the source locale",
+                  "properties": {
+                    "code": {
+                      "type": "string",
+                      "description": "Specifies the locale code of the source locale",
+                      "pattern": "^[a-z]{2}(-[a-zA-Z]{2,})?$"
+                    },
+                    "baseHref": {
+                      "type": "string",
+                      "description": "HTML base HREF to use for the locale (defaults to the locale code)"
+                    }
+                  },
+                  "additionalProperties": false
+                }
+              ]
             },
             "locales": {
               "type": "object",
               "additionalProperties": false,
               "patternProperties": {
                 "^[a-z]{2}(-[a-zA-Z]{2,})?$": {
-                  "type": "string",
-                  "description": "Localization file to use for i18n"
+                  "oneOf": [
+                    {
+                      "type": "string",
+                      "description": "Localization file to use for i18n"
+                    },
+                    {
+                      "type": "object",
+                      "description": "Localization options to use for the locale",
+                      "properties": {
+                        "translation": {
+                          "type": "string",
+                          "description": "Localization file to use for i18n"
+                        },
+                        "baseHref": {
+                          "type": "string",
+                          "description": "HTML base HREF to use for the locale (defaults to the locale code)"
+                        }
+                      },
+                      "additionalProperties": false
+                    }
+                  ]
                 }
               }
             }
diff --git a/packages/angular_devkit/build_angular/src/browser/index.ts b/packages/angular_devkit/build_angular/src/browser/index.ts
index 30cd6a8020ae..eaf1dd66651c 100644
--- a/packages/angular_devkit/build_angular/src/browser/index.ts
+++ b/packages/angular_devkit/build_angular/src/browser/index.ts
@@ -673,6 +673,16 @@ export function buildWebpackBrowser(
 
             if (options.index) {
               for (const [locale, outputPath] of outputPaths.entries()) {
+                let localeBaseHref;
+                if (i18n.locales[locale] && i18n.locales[locale].baseHref !== '') {
+                  localeBaseHref = path.posix.join(
+                    options.baseHref || '',
+                    i18n.locales[locale].baseHref === undefined
+                      ? `/${locale}/`
+                      : i18n.locales[locale].baseHref,
+                  );
+                }
+
                 try {
                   await generateIndex(
                     outputPath,
@@ -684,6 +694,7 @@ export function buildWebpackBrowser(
                     transforms.indexHtml,
                     // i18nLocale is used when Ivy is disabled
                     locale || options.i18nLocale,
+                    localeBaseHref || options.baseHref,
                   );
                 } catch (err) {
                   return { success: false, error: mapErrorToMessage(err) };
@@ -734,6 +745,7 @@ function generateIndex(
   moduleFiles: EmittedFiles[] | undefined,
   transformer?: IndexHtmlTransform,
   locale?: string,
+  baseHref?: string,
 ): Promise<void> {
   const host = new NodeJsSyncHost();
 
@@ -744,7 +756,7 @@ function generateIndex(
     files,
     noModuleFiles,
     moduleFiles,
-    baseHref: options.baseHref,
+    baseHref,
     deployUrl: options.deployUrl,
     sri: options.subresourceIntegrity,
     scripts: options.scripts,
diff --git a/packages/angular_devkit/build_angular/src/utils/i18n-options.ts b/packages/angular_devkit/build_angular/src/utils/i18n-options.ts
index ef7bed45c931..37edb09f4795 100644
--- a/packages/angular_devkit/build_angular/src/utils/i18n-options.ts
+++ b/packages/angular_devkit/build_angular/src/utils/i18n-options.ts
@@ -21,7 +21,14 @@ export interface I18nOptions {
   sourceLocale: string;
   locales: Record<
     string,
-    { file: string; format?: string; translation?: unknown; dataPath?: string, integrity?: string }
+    {
+      file: string;
+      format?: string;
+      translation?: unknown;
+      dataPath?: string;
+      integrity?: string;
+      baseHref?: string;
+    }
   >;
   flatOutput?: boolean;
   readonly shouldInline: boolean;
@@ -32,49 +39,79 @@ export function createI18nOptions(
   metadata: json.JsonObject,
   inline?: boolean | string[],
 ): I18nOptions {
-  if (
-    metadata.i18n !== undefined &&
-    (typeof metadata.i18n !== 'object' || !metadata.i18n || Array.isArray(metadata.i18n))
-  ) {
+  if (metadata.i18n !== undefined && !json.isJsonObject(metadata.i18n)) {
     throw new Error('Project i18n field is malformed. Expected an object.');
   }
   metadata = metadata.i18n || {};
 
-  if (metadata.sourceLocale !== undefined && typeof metadata.sourceLocale !== 'string') {
-    throw new Error('Project i18n sourceLocale field is malformed. Expected a string.');
-  }
-
   const i18n: I18nOptions = {
     inlineLocales: new Set<string>(),
     // en-US is the default locale added to Angular applications (https://angular.io/guide/i18n#i18n-pipes)
-    sourceLocale: metadata.sourceLocale || 'en-US',
+    sourceLocale: 'en-US',
     locales: {},
     get shouldInline() {
       return this.inlineLocales.size > 0;
     },
   };
 
-  if (
-    metadata.locales !== undefined &&
-    (!metadata.locales || typeof metadata.locales !== 'object' || Array.isArray(metadata.locales))
-  ) {
+  let rawSourceLocale;
+  let rawSourceLocaleBaseHref;
+  if (json.isJsonObject(metadata.sourceLocale)) {
+    rawSourceLocale = metadata.sourceLocale.code;
+    if (metadata.sourceLocale.baseHref !== undefined && typeof metadata.sourceLocale.baseHref !== 'string') {
+      throw new Error('Project i18n sourceLocale baseHref field is malformed. Expected a string.');
+    }
+    rawSourceLocaleBaseHref = metadata.sourceLocale.baseHref;
+  } else {
+    rawSourceLocale = metadata.sourceLocale;
+  }
+
+  if (rawSourceLocale !== undefined) {
+    if (typeof rawSourceLocale !== 'string') {
+      throw new Error('Project i18n sourceLocale field is malformed. Expected a string.');
+    }
+
+    i18n.sourceLocale = rawSourceLocale;
+  }
+
+  i18n.locales[i18n.sourceLocale] = {
+    file: '',
+    baseHref: rawSourceLocaleBaseHref,
+  };
+
+  if (metadata.locales !== undefined && !json.isJsonObject(metadata.locales)) {
     throw new Error('Project i18n locales field is malformed. Expected an object.');
   } else if (metadata.locales) {
-    for (const [locale, translationFile] of Object.entries(metadata.locales)) {
-      if (typeof translationFile !== 'string') {
+    for (const [locale, options] of Object.entries(metadata.locales)) {
+      let translationFile;
+      let baseHref;
+      if (json.isJsonObject(options)) {
+        if (typeof options.translation !== 'string') {
+          throw new Error(
+            `Project i18n locales translation field value for '${locale}' is malformed. Expected a string.`,
+          );
+        }
+        translationFile = options.translation;
+        if (typeof options.baseHref === 'string') {
+          baseHref = options.baseHref;
+        }
+      } else if (typeof options !== 'string') {
         throw new Error(
-          `Project i18n locales field value for '${locale}' is malformed. Expected a string.`,
+          `Project i18n locales field value for '${locale}' is malformed. Expected a string or object.`,
         );
+      } else {
+        translationFile = options;
       }
 
       if (locale === i18n.sourceLocale) {
         throw new Error(
-          `An i18n locale identifier ('${locale}') cannot both be a source locale and provide a translation.`,
+          `An i18n locale ('${locale}') cannot both be a source locale and provide a translation.`,
         );
       }
 
       i18n.locales[locale] = {
         file: translationFile,
+        baseHref,
       };
     }
   }
diff --git a/packages/angular_devkit/core/src/experimental/workspace/workspace-schema.json b/packages/angular_devkit/core/src/experimental/workspace/workspace-schema.json
index de7b5abec537..c03dca716f93 100644
--- a/packages/angular_devkit/core/src/experimental/workspace/workspace-schema.json
+++ b/packages/angular_devkit/core/src/experimental/workspace/workspace-schema.json
@@ -131,17 +131,57 @@
       "type": "object",
       "properties": {
         "sourceLocale": {
-          "type": "string",
-          "description": "Specifies the source language of the application.",
-          "default": "en-US"
+          "oneOf": [
+            {
+              "type": "string",
+              "description": "Specifies the source locale of the application.",
+              "default": "en-US",
+              "pattern": "^[a-z]{2}(-[a-zA-Z]{2,})?$"
+            },
+            {
+              "type": "object",
+              "description": "Localization options to use for the source locale",
+              "properties": {
+                "code": {
+                  "type": "string",
+                  "description": "Specifies the locale code of the source locale",
+                  "pattern": "^[a-z]{2}(-[a-zA-Z]{2,})?$"
+                },
+                "baseHref": {
+                  "type": "string",
+                  "description": "HTML base HREF to use for the locale (defaults to the locale code)"
+                }
+              },
+              "additionalProperties": false
+            }
+          ]
         },
         "locales": {
           "type": "object",
           "additionalProperties": false,
           "patternProperties": {
             "^[a-z]{2}(-[a-zA-Z]{2,})?$": {
-              "type": "string",
-              "description": "Localization file to use for i18n."
+              "oneOf": [
+                {
+                  "type": "string",
+                  "description": "Localization file to use for i18n"
+                },
+                {
+                  "type": "object",
+                  "description": "Localization options to use for the locale",
+                  "properties": {
+                    "translation": {
+                      "type": "string",
+                      "description": "Localization file to use for i18n"
+                    },
+                    "baseHref": {
+                      "type": "string",
+                      "description": "HTML base HREF to use for the locale (defaults to the locale code)"
+                    }
+                  },
+                  "additionalProperties": false
+                }
+              ]
             }
           }
         }
diff --git a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-basehref.ts b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-basehref.ts
new file mode 100644
index 000000000000..51ad75da4699
--- /dev/null
+++ b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-basehref.ts
@@ -0,0 +1,103 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import { expectFileToMatch } from '../../utils/fs';
+import { ng } from '../../utils/process';
+import { updateJsonFile } from '../../utils/project';
+import { externalServer, langTranslations, setupI18nConfig } from './legacy';
+
+const baseHrefs = {
+  'en-US': '/en/',
+  fr: '/fr-FR/',
+  de: '',
+};
+
+export default async function() {
+  // Setup i18n tests and config.
+  await setupI18nConfig(true);
+
+  // Update angular.json
+  await updateJsonFile('angular.json', workspaceJson => {
+    const appProject = workspaceJson.projects['test-project'];
+    // tslint:disable-next-line: no-any
+    const i18n: Record<string, any> = appProject.i18n;
+
+    i18n.sourceLocale = {
+      baseHref: baseHrefs['en-US'],
+    };
+
+    i18n.locales['fr'] = {
+      translation: i18n.locales['fr'],
+      baseHref: baseHrefs['fr'],
+    };
+
+    i18n.locales['de'] = {
+      translation: i18n.locales['de'],
+      baseHref: baseHrefs['de'],
+    };
+  });
+
+  // Build each locale and verify the output.
+  await ng('build');
+  for (const { lang, outputPath } of langTranslations) {
+    if (baseHrefs[lang] === undefined) {
+      throw new Error('Invalid E2E test setup: unexpected locale ' + lang);
+    }
+
+    // Verify the HTML lang attribute is present
+    await expectFileToMatch(`${outputPath}/index.html`, `lang="${lang}"`);
+
+    // Verify the HTML base HREF attribute is present
+    await expectFileToMatch(`${outputPath}/index.html`, `href="${baseHrefs[lang] || '/'}"`);
+
+    // Execute Application E2E tests with dev server
+    await ng('e2e', `--configuration=${lang}`, '--port=0');
+
+    // Execute Application E2E tests for a production build without dev server
+    const server = externalServer(outputPath, baseHrefs[lang] || '/');
+    try {
+      await ng(
+        'e2e',
+        `--configuration=${lang}`,
+        '--devServerTarget=',
+        `--baseUrl=http://localhost:4200${baseHrefs[lang] || '/'}`,
+      );
+    } finally {
+      server.close();
+    }
+  }
+
+  // Update angular.json
+  await updateJsonFile('angular.json', workspaceJson => {
+    const appArchitect = workspaceJson.projects['test-project'].architect;
+
+    appArchitect['build'].options.baseHref = '/test/';
+  });
+
+  // Build each locale and verify the output.
+  await ng('build');
+  for (const { lang, outputPath } of langTranslations) {
+    // Verify the HTML base HREF attribute is present
+    await expectFileToMatch(`${outputPath}/index.html`, `href="/test${baseHrefs[lang] || '/'}"`);
+
+    // Execute Application E2E tests with dev server
+    await ng('e2e', `--configuration=${lang}`, '--port=0');
+
+    // Execute Application E2E tests for a production build without dev server
+    const server = externalServer(outputPath, '/test' + (baseHrefs[lang] || '/'));
+    try {
+      await ng(
+        'e2e',
+        `--configuration=${lang}`,
+        '--devServerTarget=',
+        `--baseUrl=http://localhost:4200/test${baseHrefs[lang] || '/'}`,
+      );
+    } finally {
+      server.close();
+    }
+  }
+}
diff --git a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-dl-xliff2.ts b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-dl-xliff2.ts
index cc45fdc6202b..28225d45a583 100644
--- a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-dl-xliff2.ts
+++ b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-dl-xliff2.ts
@@ -34,6 +34,9 @@ export async function executeTest() {
     // Verify the HTML lang attribute is present
     await expectFileToMatch(`${outputPath}/index.html`, `lang="${lang}"`);
 
+    // Verify the HTML base HREF attribute is present
+    await expectFileToMatch(`${outputPath}/index.html`, `href="/${lang}/"`);
+
     // Verify the locale data is registered using the global files
     await expectFileToMatch(`${outputPath}/vendor-es5.js`, '.ng.common.locales');
     await expectFileToMatch(`${outputPath}/vendor-es2015.js`, '.ng.common.locales');
@@ -42,9 +45,14 @@ export async function executeTest() {
     await ng('e2e', `--configuration=${lang}`, '--port=0');
 
     // Execute Application E2E tests for a production build without dev server
-    const server = externalServer(outputPath);
+    const server = externalServer(outputPath, `/${lang}/`);
     try {
-      await ng('e2e', `--configuration=${lang}`, '--devServerTarget=');
+      await ng(
+        'e2e',
+        `--configuration=${lang}`,
+        '--devServerTarget=',
+        `--baseUrl=http://localhost:4200/${lang}/`,
+      );
     } finally {
       server.close();
     }
diff --git a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es2015.ts b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es2015.ts
index 4e3901f4cd13..a0d9148277f4 100644
--- a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es2015.ts
+++ b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es2015.ts
@@ -29,9 +29,14 @@ export default async function() {
     await ng('e2e', `--configuration=${lang}`, '--port=0');
 
     // Execute Application E2E tests for a production build without dev server
-    const server = externalServer(outputPath);
+    const server = externalServer(outputPath, `/${lang}/`);
     try {
-      await ng('e2e', `--configuration=${lang}`, '--devServerTarget=');
+      await ng(
+        'e2e',
+        `--configuration=${lang}`,
+        '--devServerTarget=',
+        `--baseUrl=http://localhost:4200/${lang}/`,
+      );
     } finally {
       server.close();
     }
diff --git a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es5.ts b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es5.ts
index eee1e7251827..656db6ec58f6 100644
--- a/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es5.ts
+++ b/tests/legacy-cli/e2e/tests/i18n/ivy-localize-es5.ts
@@ -29,9 +29,14 @@ export default async function() {
     await ng('e2e', `--configuration=${lang}`, '--port=0');
 
     // Execute Application E2E tests for a production build without dev server
-    const server = externalServer(outputPath);
+    const server = externalServer(outputPath, `/${lang}/`);
     try {
-      await ng('e2e', `--configuration=${lang}`, '--devServerTarget=');
+      await ng(
+        'e2e',
+        `--configuration=${lang}`,
+        '--devServerTarget=',
+        `--baseUrl=http://localhost:4200/${lang}/`,
+      );
     } finally {
       server.close();
     }
diff --git a/tests/legacy-cli/e2e/tests/i18n/legacy.ts b/tests/legacy-cli/e2e/tests/i18n/legacy.ts
index ff02cbba1b0c..d40d900421c4 100644
--- a/tests/legacy-cli/e2e/tests/i18n/legacy.ts
+++ b/tests/legacy-cli/e2e/tests/i18n/legacy.ts
@@ -56,9 +56,9 @@ export const langTranslations = [
 ];
 export const sourceLocale = langTranslations[0].lang;
 
-export const externalServer = (outputPath: string) => {
+export const externalServer = (outputPath: string, baseUrl = '/') => {
   const app = express();
-  app.use(express.static(resolve(outputPath)));
+  app.use(baseUrl, express.static(resolve(outputPath)));
 
   // call .close() on the return value to close the server.
   return app.listen(4200, 'localhost');
diff --git a/tests/legacy-cli/e2e/tests/i18n/ve-localize-es2015.ts b/tests/legacy-cli/e2e/tests/i18n/ve-localize-es2015.ts
index c02c411454b9..91194763444a 100644
--- a/tests/legacy-cli/e2e/tests/i18n/ve-localize-es2015.ts
+++ b/tests/legacy-cli/e2e/tests/i18n/ve-localize-es2015.ts
@@ -44,9 +44,14 @@ export default async function() {
     await ng('e2e', `--configuration=${lang}`, '--port=0');
 
     // Execute Application E2E tests for a production build without dev server
-    const server = externalServer(outputPath);
+    const server = externalServer(outputPath, `/${lang}/`);
     try {
-      await ng('e2e', `--configuration=${lang}`, '--devServerTarget=');
+      await ng(
+        'e2e',
+        `--configuration=${lang}`,
+        '--devServerTarget=',
+        `--baseUrl=http://localhost:4200/${lang}/`,
+      );
     } finally {
       server.close();
     }