diff --git a/packages/schematics/angular/migrations/migration-collection.json b/packages/schematics/angular/migrations/migration-collection.json
index 8f9fe5ac3b..c0efd4bef8 100644
--- a/packages/schematics/angular/migrations/migration-collection.json
+++ b/packages/schematics/angular/migrations/migration-collection.json
@@ -144,6 +144,11 @@
       "version": "12.0.0-next.4",
       "factory": "./update-8/#updateLazyModulePaths",
       "description": "Lazy loading syntax migration. Update lazy loading string syntax to use dynamic imports."
+    },
+    "production-by-default": {
+      "version": "9999.0.0",
+      "factory": "./update-12/production-default-config",
+      "description": "Optional migration to update Angular CLI workspace configurations to 'production' mode by default."
     }
   }
 }
diff --git a/packages/schematics/angular/migrations/update-12/production-default-config.ts b/packages/schematics/angular/migrations/update-12/production-default-config.ts
new file mode 100644
index 0000000000..272972b1cd
--- /dev/null
+++ b/packages/schematics/angular/migrations/update-12/production-default-config.ts
@@ -0,0 +1,132 @@
+/**
+ * @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 { JsonValue, logging, tags, workspaces } from '@angular-devkit/core';
+import { Rule } from '@angular-devkit/schematics';
+import { allTargetOptions, allWorkspaceTargets, updateWorkspace } from '../../utility/workspace';
+import { Builders } from '../../utility/workspace-models';
+
+export default function (): Rule {
+  return async (_host, context) => updateWorkspace(workspace => {
+    for (const [name, target] of allWorkspaceTargets(workspace)) {
+      let defaultConfiguration: string | undefined;
+
+      // Only interested in 1st party builders
+      switch (target.builder) {
+        case Builders.AppShell:
+        case Builders.Browser:
+        case Builders.Server:
+        case Builders.NgPackagr:
+          defaultConfiguration = 'production';
+          break;
+        case Builders.DevServer:
+        case Builders.Protractor:
+        case '@nguniversal/builders:ssr-dev-server':
+          defaultConfiguration = 'development';
+          break;
+        case Builders.TsLint:
+        case Builders.ExtractI18n:
+        case Builders.Karma:
+          // Nothing to update
+          break;
+        default:
+          context.logger.warn(tags.stripIndents`Cannot update "${name}" target configuration as it's using "${target.builder}"
+          which is a third-party builder. This target configuration will require manual review.`);
+
+          continue;
+      }
+
+      if (!defaultConfiguration) {
+        continue;
+      }
+
+      updateTarget(name, target, context.logger, defaultConfiguration);
+    }
+  });
+}
+
+function getArchitectTargetWithConfig(currentTarget: string, overrideConfig?: string): string {
+  const [project, target, config = 'development'] = currentTarget.split(':');
+
+  return `${project}:${target}:${overrideConfig || config}`;
+}
+
+function updateTarget(
+  targetName: string,
+  target: workspaces.TargetDefinition,
+  logger: logging.LoggerApi,
+  defaultConfiguration: string,
+): void {
+  if (!target.configurations) {
+    target.configurations = {};
+  }
+
+  if (target.configurations?.development) {
+    logger.info(tags.stripIndents`Skipping updating "${targetName}" target configuration as a "development" configuration is already defined.`);
+
+    return;
+  }
+
+  if (!target.configurations?.production) {
+    logger.info(tags.stripIndents`Skipping updating "${targetName}" target configuration as a "production" configuration is not defined.`);
+
+    return;
+  }
+
+  const developmentOptions: Record<string, JsonValue | undefined> = {};
+  let serverTarget = true;
+  let browserTarget = true;
+  let devServerTarget = true;
+
+  for (const [, options] of allTargetOptions(target)) {
+    if (typeof options.serverTarget === 'string') {
+      options.serverTarget = getArchitectTargetWithConfig(options.serverTarget);
+      if (!developmentOptions.serverTarget) {
+        developmentOptions.serverTarget = getArchitectTargetWithConfig(options.serverTarget, 'development');
+      }
+    } else {
+      serverTarget = false;
+    }
+
+    if (typeof options.browserTarget === 'string') {
+      options.browserTarget = getArchitectTargetWithConfig(options.browserTarget);
+      if (!developmentOptions.browserTarget) {
+        developmentOptions.browserTarget = getArchitectTargetWithConfig(options.browserTarget, 'development');
+      }
+    } else {
+      browserTarget = false;
+    }
+
+    if (typeof options.devServerTarget === 'string') {
+      options.devServerTarget = getArchitectTargetWithConfig(options.devServerTarget);
+      if (!developmentOptions.devServerTarget) {
+        developmentOptions.devServerTarget = getArchitectTargetWithConfig(options.devServerTarget, 'development');
+      }
+    } else {
+      devServerTarget = false;
+    }
+  }
+
+  // If all configurastions have a target defined delete the one in options.
+  if (target.options) {
+    if (serverTarget) {
+      delete target.options.serverTarget;
+    }
+
+    if (browserTarget) {
+      delete target.options.browserTarget;
+    }
+
+    if (devServerTarget) {
+      delete target.options.devServerTarget;
+    }
+  }
+
+  target.defaultConfiguration = defaultConfiguration;
+  target.configurations.development = developmentOptions;
+}
diff --git a/packages/schematics/angular/migrations/update-12/production-default-config_spec.ts b/packages/schematics/angular/migrations/update-12/production-default-config_spec.ts
new file mode 100644
index 0000000000..45076c7d1c
--- /dev/null
+++ b/packages/schematics/angular/migrations/update-12/production-default-config_spec.ts
@@ -0,0 +1,310 @@
+/**
+ * @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 { JsonObject } from '@angular-devkit/core';
+import { EmptyTree } from '@angular-devkit/schematics';
+import { SchematicTestRunner, UnitTestTree } from '@angular-devkit/schematics/testing';
+import { Builders, ProjectType, WorkspaceSchema } from '../../utility/workspace-models';
+
+function getArchitect(tree: UnitTestTree): JsonObject {
+  return JSON.parse(tree.readContent('/angular.json')).projects.app.architect;
+}
+
+function createWorkSpaceConfig(tree: UnitTestTree) {
+  const angularConfig: WorkspaceSchema = {
+    version: 1,
+    projects: {
+      app: {
+        root: '',
+        sourceRoot: 'src',
+        projectType: ProjectType.Application,
+        prefix: 'app',
+        architect: {
+          browser: {
+            builder: Builders.Browser,
+            options: {
+              outputPath: 'dist/integration-project',
+              index: 'src/index.html',
+              main: 'src/main.ts',
+              polyfills: 'src/polyfills.ts',
+              tsConfig: 'tsconfig.app.json',
+              aot: true,
+              sourceMap: true,
+              assets: [
+                'src/favicon.ico',
+                'src/assets',
+              ],
+              styles: [
+                'src/styles.css',
+              ],
+              scripts: [],
+            },
+            configurations: {
+              production: {
+                deployUrl: 'http://cdn.com',
+                fileReplacements: [{
+                  replace: 'src/environments/environment.ts',
+                  with: 'src/environments/environment.prod.ts',
+                }],
+                optimization: true,
+                outputHashing: 'all',
+                sourceMap: false,
+                namedChunks: false,
+                extractLicenses: true,
+                vendorChunk: false,
+                buildOptimizer: true,
+                watch: true,
+                budgets: [{
+                  type: 'initial',
+                  maximumWarning: '2mb',
+                  maximumError: '5mb',
+                }],
+              },
+              optimization_sm: {
+                sourceMap: true,
+                optimization: true,
+                namedChunks: false,
+                vendorChunk: true,
+                buildOptimizer: true,
+              },
+            },
+          },
+          ng_packagr: {
+            builder: Builders.NgPackagr,
+            options: {
+              watch: true,
+              tsConfig: 'projects/lib/tsconfig.lib.json',
+            },
+            configurations: {
+              production: {
+                watch: false,
+                tsConfig: 'projects/lib/tsconfig.lib.prod.json',
+              },
+            },
+          },
+          dev_server: {
+            builder: Builders.DevServer,
+            options: {
+              browserTarget: 'app:build',
+              watch: false,
+            },
+            configurations: {
+              production: {
+                browserTarget: 'app:build:production',
+              },
+              optimization_sm: {
+                browserTarget: 'app:build:optimization_sm',
+              },
+            },
+          },
+          app_shell: {
+            builder: Builders.AppShell,
+            options: {
+              browserTarget: 'app:build',
+              serverTarget: 'app:server',
+            },
+            configurations: {
+              optimization_sm: {
+                browserTarget: 'app:build:optimization_sm',
+                serverTarget: 'app:server:optimization_sm',
+              },
+              production: {
+                browserTarget: 'app:build:production',
+                serverTarget: 'app:server:optimization_sm',
+              },
+            },
+          },
+          server: {
+            builder: Builders.Server,
+            options: {
+              outputPath: 'dist/server',
+              main: 'server.ts',
+              tsConfig: 'tsconfig.server.json',
+              optimization: false,
+              sourceMap: true,
+            },
+            configurations: {
+              optimization_sm: {
+                sourceMap: true,
+                optimization: true,
+              },
+              production: {
+                fileReplacements: [
+                  {
+                    replace: 'src/environments/environment.ts',
+                    with: 'src/environments/environment.prod.ts',
+                  },
+                ],
+                sourceMap: false,
+                optimization: true,
+              },
+            },
+          },
+        },
+      },
+    },
+  };
+
+  tree.create('/angular.json', JSON.stringify(angularConfig, undefined, 2));
+}
+
+const schematicName = 'production-by-default';
+describe(`Migration to update 'angular.json' configurations to production by default. ${schematicName}`, () => {
+  const schematicRunner = new SchematicTestRunner(
+    'migrations',
+    require.resolve('../migration-collection.json'),
+  );
+
+  let tree: UnitTestTree;
+  beforeEach(() => {
+    tree = new UnitTestTree(new EmptyTree());
+    createWorkSpaceConfig(tree);
+  });
+
+  it('update browser builder configurations', async () => {
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { browser } = getArchitect(newTree);
+    const output = {
+      builder: '@angular-devkit/build-angular:browser',
+      options: {
+        outputPath: 'dist/integration-project',
+        index: 'src/index.html',
+        main: 'src/main.ts',
+        polyfills: 'src/polyfills.ts',
+        tsConfig: 'tsconfig.app.json',
+        aot: true,
+        sourceMap: true,
+        assets: ['src/favicon.ico', 'src/assets'],
+        styles: ['src/styles.css'],
+        scripts: [],
+      },
+      configurations: {
+        production: {
+          deployUrl: 'http://cdn.com',
+          optimization: true,
+          outputHashing: 'all',
+          sourceMap: false,
+          namedChunks: false,
+          extractLicenses: true,
+          vendorChunk: false,
+          buildOptimizer: true,
+          watch: true,
+          fileReplacements: [{
+            replace: 'src/environments/environment.ts',
+            with: 'src/environments/environment.prod.ts',
+          }],
+          budgets: [{
+            type: 'initial',
+            maximumWarning: '2mb',
+            maximumError: '5mb',
+          }],
+        },
+        optimization_sm: {
+          sourceMap: true,
+          optimization: true,
+          namedChunks: false,
+          vendorChunk: true,
+          buildOptimizer: true,
+        },
+        development: {},
+      },
+      defaultConfiguration: 'production',
+    };
+
+    expect(browser).toEqual(output);
+  });
+
+  it('update ng-packagr builder configurations', async () => {
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { ng_packagr } = getArchitect(newTree);
+    const output = {
+      builder: '@angular-devkit/build-angular:ng-packagr',
+      options: { watch: true, tsConfig: 'projects/lib/tsconfig.lib.json' },
+      configurations: {
+        production: { watch: false, tsConfig: 'projects/lib/tsconfig.lib.prod.json' },
+        development: {},
+      },
+      defaultConfiguration: 'production',
+    };
+
+    expect(ng_packagr).toEqual(output);
+  });
+
+  it('update dev-server builder configurations', async () => {
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { dev_server } = getArchitect(newTree);
+    const output = {
+      builder: '@angular-devkit/build-angular:dev-server',
+      options: { watch: false },
+      configurations: {
+        production: { browserTarget: 'app:build:production' },
+        optimization_sm: { browserTarget: 'app:build:optimization_sm' },
+        development: { browserTarget: 'app:build:development' },
+      },
+      defaultConfiguration: 'development',
+    };
+
+    expect(dev_server).toEqual(output);
+  });
+
+  it('update server builder configurations', async () => {
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { server } = getArchitect(newTree);
+    const output = {
+      builder: '@angular-devkit/build-angular:server',
+      options: {
+        outputPath: 'dist/server',
+        main: 'server.ts',
+        tsConfig: 'tsconfig.server.json',
+        optimization: false,
+        sourceMap: true,
+      },
+      configurations: {
+        optimization_sm: { sourceMap: true, optimization: true },
+        production: {
+          fileReplacements: [{
+            replace: 'src/environments/environment.ts',
+            with: 'src/environments/environment.prod.ts',
+          }],
+          sourceMap: false,
+          optimization: true,
+        },
+        development: {},
+      },
+      defaultConfiguration: 'production',
+    };
+
+    expect(server).toEqual(output);
+  });
+
+  it('update app-shell builder configurations', async () => {
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { app_shell } = getArchitect(newTree);
+
+    const output = {
+      builder: '@angular-devkit/build-angular:app-shell',
+      options: {},
+      configurations: {
+        optimization_sm: {
+          browserTarget: 'app:build:optimization_sm',
+          serverTarget: 'app:server:optimization_sm',
+        },
+        production: {
+          browserTarget: 'app:build:production',
+          serverTarget: 'app:server:optimization_sm',
+        },
+        development: {
+          serverTarget: 'app:server:development',
+          browserTarget: 'app:build:development',
+        },
+      },
+      defaultConfiguration: 'production',
+    };
+
+    expect(app_shell).toEqual(output);
+  });
+});
diff --git a/packages/schematics/angular/utility/workspace-models.ts b/packages/schematics/angular/utility/workspace-models.ts
index 248d4ab7a4..1113946fe1 100644
--- a/packages/schematics/angular/utility/workspace-models.ts
+++ b/packages/schematics/angular/utility/workspace-models.ts
@@ -76,7 +76,7 @@ export interface ServerBuilderOptions {
   tsConfig: string;
   main: string;
   fileReplacements?: FileReplacements[];
-  optimization?: {
+  optimization?: boolean | {
     scripts?: boolean;
     styles?: boolean;
   };