diff --git a/src/material/schematics/ng-generate/theming-api/config.ts b/src/material/schematics/ng-generate/theming-api/config.ts
index b13b2414632a..aa4fc415313a 100644
--- a/src/material/schematics/ng-generate/theming-api/config.ts
+++ b/src/material/schematics/ng-generate/theming-api/config.ts
@@ -103,8 +103,8 @@ export const cdkMixins: Record<string, string> = {
 export const removedMaterialVariables: Record<string, string> = {
   // Note: there's also a usage of a variable called `$pi`, but the name is short enough that
   // it matches things like `$mat-pink`. Don't migrate it since it's unlikely to be used.
-  'mat-xsmall': `'max-width: 599px'`,
-  'mat-small': `'max-width: 959px'`,
+  'mat-xsmall': 'max-width: 599px',
+  'mat-small': 'max-width: 959px',
   'mat-toggle-padding': '8px',
   'mat-toggle-size': '20px',
   'mat-linear-out-slow-in-timing-function': 'cubic-bezier(0, 0, 0.2, 0.1)',
diff --git a/src/material/schematics/ng-generate/theming-api/index.spec.ts b/src/material/schematics/ng-generate/theming-api/index.spec.ts
index 56ce8288ef87..8514da7de586 100644
--- a/src/material/schematics/ng-generate/theming-api/index.spec.ts
+++ b/src/material/schematics/ng-generate/theming-api/index.spec.ts
@@ -195,6 +195,23 @@ describe('Material theming API schematic', () => {
     ]);
   });
 
+  it('should migrate files that import the Material APIs transitively', async () => {
+    const app = await createTestApp(runner);
+    app.create('/theme.scss', [
+      `@import 're-exports-material-symbols';`,
+      `@include mat-core();`,
+      `@include mat-button-theme();`,
+    ].join('\n'));
+
+    const tree = await runner.runSchematicAsync('theming-api', options, app).toPromise();
+    expect(getFileContent(tree, '/theme.scss').split('\n')).toEqual([
+      `@use '~@angular/material' as mat;`,
+      `@import 're-exports-material-symbols';`,
+      `@include mat.core();`,
+      `@include mat.button-theme();`,
+    ]);
+  });
+
   it('should allow an arbitrary number of spaces after @include and @import', async () => {
     const app = await createTestApp(runner);
     app.create('/theme.scss', [
@@ -485,7 +502,7 @@ describe('Material theming API schematic', () => {
     ]);
   });
 
-  it('should not change files if they have an import, but do not use any symbols', async () => {
+  it('should drop the old import path even if the file is not using any symbols', async () => {
     const app = await createTestApp(runner);
     app.create('/theme.scss', [
       `@import '~@angular/material/theming';`,
@@ -497,8 +514,6 @@ describe('Material theming API schematic', () => {
 
     const tree = await runner.runSchematicAsync('theming-api', options, app).toPromise();
     expect(getFileContent(tree, '/theme.scss').split('\n')).toEqual([
-      `@import '~@angular/material/theming';`,
-      ``,
       `.my-dialog {`,
         `color: red;`,
       `}`,
@@ -537,7 +552,7 @@ describe('Material theming API schematic', () => {
         `transition: all 400ms cubic-bezier(0.25, 0.8, 0.25, 1);`,
       `}`,
       ``,
-      `@media ('max-width: 959px') {`,
+      `@media (max-width: 959px) {`,
         `.my-button-toggle {`,
           `height: 24px;`,
         `}`,
@@ -571,4 +586,22 @@ describe('Material theming API schematic', () => {
     ]);
   });
 
+  it('should not migrate files in the node_modules', async () => {
+    const app = await createTestApp(runner);
+    app.create('/node_modules/theme.scss', [
+      `@import '~@angular/material/theming';`,
+      ``,
+      `@include mat-button-toggle-theme();`,
+      ``,
+    ].join('\n'));
+
+    const tree = await runner.runSchematicAsync('theming-api', options, app).toPromise();
+    expect(getFileContent(tree, '/node_modules/theme.scss').split('\n')).toEqual([
+      `@import '~@angular/material/theming';`,
+      ``,
+      `@include mat-button-toggle-theme();`,
+      ``,
+    ]);
+  });
+
 });
diff --git a/src/material/schematics/ng-generate/theming-api/index.ts b/src/material/schematics/ng-generate/theming-api/index.ts
index b8c3a1143993..73cb0ba50018 100644
--- a/src/material/schematics/ng-generate/theming-api/index.ts
+++ b/src/material/schematics/ng-generate/theming-api/index.ts
@@ -14,7 +14,7 @@ import {migrateFileContent} from './migration';
 export default function(_options: Schema): Rule {
   return (tree: Tree) => {
     tree.visit((path, entry) => {
-      if (extname(path) === '.scss') {
+      if (extname(path) === '.scss' && path.indexOf('node_modules') === -1) {
         const content = entry?.content.toString();
         const migratedContent = content ? migrateFileContent(content,
           '~@angular/material/', '~@angular/cdk/', '~@angular/material', '~@angular/cdk') : content;
diff --git a/src/material/schematics/ng-generate/theming-api/migration.ts b/src/material/schematics/ng-generate/theming-api/migration.ts
index a46734677ca3..38a971d5ba7c 100644
--- a/src/material/schematics/ng-generate/theming-api/migration.ts
+++ b/src/material/schematics/ng-generate/theming-api/migration.ts
@@ -37,19 +37,21 @@ export function migrateFileContent(content: string,
   const materialResults = detectImports(content, oldMaterialPrefix);
   const cdkResults = detectImports(content, oldCdkPrefix);
 
-  // If there are no imports, we don't need to go further.
-  if (materialResults.imports.length > 0 || cdkResults.imports.length > 0) {
-    const initialContent = content;
-    content = migrateMaterialSymbols(content, newMaterialImportPath, materialResults.namespaces);
-    content = migrateCdkSymbols(content, newCdkImportPath, cdkResults.namespaces);
-
-    // Only drop the imports if any of the symbols were used within the file.
-    if (content !== initialContent) {
-      content = removeStrings(content, materialResults.imports);
-      content = removeStrings(content, cdkResults.imports);
-      content = content.replace(/^\s+/, '');
-      content = replaceRemovedVariables(content, removedMaterialVariables);
-    }
+  // Try to migrate the symbols even if there are no imports. This is used
+  // to cover the case where the Components symbols were used transitively.
+  content = migrateMaterialSymbols(content, newMaterialImportPath, materialResults.namespaces);
+  content = migrateCdkSymbols(content, newCdkImportPath, cdkResults.namespaces);
+  content = replaceRemovedVariables(content, removedMaterialVariables);
+
+  // We can assume that the migration has taken care of any Components symbols that were
+  // imported transitively so we can always drop the old imports. We also assume that imports
+  // to the new entry points have been added already.
+  if (materialResults.imports.length) {
+    content = removeStrings(content, materialResults.imports);
+  }
+
+  if (cdkResults.imports.length) {
+    content = removeStrings(content, cdkResults.imports);
   }
 
   return content;
@@ -227,7 +229,9 @@ function sortLengthDescending(a: string, b: string) {
 
 /** Removes all strings from another string. */
 function removeStrings(content: string, toRemove: string[]): string {
-  return toRemove.reduce((accumulator, current) => accumulator.replace(current, ''), content);
+  return toRemove
+    .reduce((accumulator, current) => accumulator.replace(current, ''), content)
+    .replace(/^\s+/, '');
 }
 
 /** Parses out the namespace from a Sass `@use` statement. */