diff --git a/src/command/use/commands/brand.ts b/src/command/use/commands/brand.ts
index 6dac4b0dd07..53bdc4e50d7 100644
--- a/src/command/use/commands/brand.ts
+++ b/src/command/use/commands/brand.ts
@@ -24,9 +24,92 @@ import { InternalError } from "../../../core/lib/error.ts";
 import { notebookContext } from "../../../render/notebook/notebook-context.ts";
 import { projectContext } from "../../../project/project-context.ts";
 import { afterConfirm } from "../../../tools/tools-console.ts";
+import { readYaml } from "../../../core/yaml.ts";
+import { Metadata } from "../../../config/types.ts";
 
 const kRootTemplateName = "template.qmd";
 
+// Brand extension detection result
+interface BrandExtensionInfo {
+  isBrandExtension: boolean;
+  extensionDir?: string; // Directory containing the brand extension
+  brandFileName?: string; // The original brand file name (e.g., "brand.yml")
+}
+
+// Check if a directory contains a brand extension
+function checkForBrandExtension(dir: string): BrandExtensionInfo {
+  const extensionFiles = ["_extension.yml", "_extension.yaml"];
+
+  for (const file of extensionFiles) {
+    const path = join(dir, file);
+    if (existsSync(path)) {
+      try {
+        const yaml = readYaml(path) as Metadata;
+        // Check for contributes.metadata.project.brand
+        const contributes = yaml?.contributes as Metadata | undefined;
+        const metadata = contributes?.metadata as Metadata | undefined;
+        const project = metadata?.project as Metadata | undefined;
+        const brandFile = project?.brand as string | undefined;
+
+        if (brandFile && typeof brandFile === "string") {
+          return {
+            isBrandExtension: true,
+            extensionDir: dir,
+            brandFileName: brandFile,
+          };
+        }
+      } catch {
+        // If we can't read/parse the extension file, continue searching
+      }
+    }
+  }
+
+  return { isBrandExtension: false };
+}
+
+// Search for a brand extension in the staged directory
+// Searches: root, _extensions/*, _extensions/*/*
+function findBrandExtension(stagedDir: string): BrandExtensionInfo {
+  // First check the root directory
+  const rootCheck = checkForBrandExtension(stagedDir);
+  if (rootCheck.isBrandExtension) {
+    return rootCheck;
+  }
+
+  // Check _extensions directory
+  const extensionsDir = join(stagedDir, "_extensions");
+  if (!existsSync(extensionsDir)) {
+    return { isBrandExtension: false };
+  }
+
+  try {
+    // Check direct children: _extensions/extension-name/
+    for (const entry of Deno.readDirSync(extensionsDir)) {
+      if (!entry.isDirectory) continue;
+
+      const extPath = join(extensionsDir, entry.name);
+      const check = checkForBrandExtension(extPath);
+      if (check.isBrandExtension) {
+        return check;
+      }
+
+      // Check nested: _extensions/org/extension-name/
+      for (const nested of Deno.readDirSync(extPath)) {
+        if (!nested.isDirectory) continue;
+        const nestedPath = join(extPath, nested.name);
+        const nestedCheck = checkForBrandExtension(nestedPath);
+        if (nestedCheck.isBrandExtension) {
+          return nestedCheck;
+        }
+      }
+    }
+  } catch {
+    // Directory read error, return not found
+  }
+
+  return { isBrandExtension: false };
+}
+
 export const useBrandCommand = new Command()
   .name("brand")
   .arguments("<target:string>")
@@ -100,8 +183,24 @@ async function useBrand(
   // Extract and move the template into place
   const stagedDir = await stageBrand(source, tempContext);
 
+  // Check if this is a brand extension
+  const brandExtInfo = findBrandExtension(stagedDir);
+
+  // Determine the actual source directory and file mapping
+  const sourceDir = brandExtInfo.isBrandExtension
+    ? brandExtInfo.extensionDir!
+    : stagedDir;
+
   // Filter the list to template files
-  const filesToCopy = templateFiles(stagedDir);
+  let filesToCopy = templateFiles(sourceDir);
+
+  // For brand extensions, exclude _extension.yml/_extension.yaml
+  if (brandExtInfo.isBrandExtension) {
+    filesToCopy = filesToCopy.filter((f) => {
+      const name = basename(f);
+      return name !== "_extension.yml" && name !== "_extension.yaml";
+    });
+  }
 
   // Confirm changes to brand directory (skip for dry-run or force)
   if (!options.dryRun && !options.force) {
@@ -125,10 +224,20 @@ async function useBrand(
   }
 
   // Build set of source file paths for comparison
+  // For brand extensions, we need to account for the brand file rename
   const sourceFiles = new Set(
     filesToCopy
       .filter((f) => !Deno.statSync(f).isDirectory)
-      .map((f) => relative(stagedDir, f)),
+      .map((f) => {
+        const rel = relative(sourceDir, f);
+        // If this is a brand extension and this is the brand file, it will become _brand.yml
+        if (
+          brandExtInfo.isBrandExtension && rel === brandExtInfo.brandFileName
+        ) {
+          return "_brand.yml";
+        }
+        return rel;
+      }),
   );
 
   // Find extra files in target that aren't in source
@@ -147,13 +256,20 @@ async function useBrand(
 
   for (const fileToCopy of filesToCopy) {
     const isDir = Deno.statSync(fileToCopy).isDirectory;
-    const rel = relative(stagedDir, fileToCopy);
+    const rel = relative(sourceDir, fileToCopy);
     if (isDir) {
       continue;
     }
+
+    // For brand extensions, rename the brand file to _brand.yml
+    let targetRel = rel;
+    if (brandExtInfo.isBrandExtension && rel === brandExtInfo.brandFileName) {
+      targetRel = "_brand.yml";
+    }
+
     // Compute the paths
-    const targetPath = join(brandDir, rel);
-    const displayName = rel;
+    const targetPath = join(brandDir, targetRel);
+    const displayName = targetRel;
     const targetDir = dirname(targetPath);
     const copyAction = {
       file: displayName,
@@ -387,10 +503,10 @@ async function ensureBrandDirectory(force: boolean, dryRun: boolean) {
   const currentDir = Deno.cwd();
   const nbContext = notebookContext();
   const project = await projectContext(currentDir, nbContext);
-  if (!project) {
-    throw new Error(`Could not find project dir for ${currentDir}`);
-  }
-  const brandDir = join(project.dir, "_brand");
+  // Use project directory if available, otherwise fall back to current directory
+  // (single-file mode without _quarto.yml)
+  const baseDir = project?.dir ?? currentDir;
+  const brandDir = join(baseDir, "_brand");
   if (!existsSync(brandDir)) {
     if (dryRun) {
       info(`  Would create directory: _brand/`);
diff --git a/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/_extension.yml b/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/_extension.yml
new file mode 100644
index 00000000000..30faf6b6004
--- /dev/null
+++ b/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/_extension.yml
@@ -0,0 +1,8 @@
+title: Test Brand Extension
+author: Test Author
+version: 1.0.0
+quarto-required: ">=1.4.0"
+contributes:
+  metadata:
+    project:
+      brand: brand.yml
diff --git a/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/brand.yml b/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/brand.yml
new file mode 100644
index 00000000000..f1d27b165e4
--- /dev/null
+++ b/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/brand.yml
@@ -0,0 +1,5 @@
+meta:
+  name: Test Brand Extension
+color:
+  primary: "#007bff"
+  secondary: "#6c757d"
diff --git a/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/logo.png b/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/logo.png
new file mode 100644
index 00000000000..c8ba37dd5c9
Binary files /dev/null and b/tests/smoke/use-brand/brand-extension/_extensions/test-org/test-brand/logo.png differ
diff --git a/tests/smoke/use/brand.test.ts b/tests/smoke/use/brand.test.ts
index 766f26ca410..01fbaba0a59 100644
--- a/tests/smoke/use/brand.test.ts
+++ b/tests/smoke/use/brand.test.ts
@@ -327,18 +327,22 @@ testQuartoCmd(
   "quarto use brand - nested directory structure"
 );
 
-// Scenario 8: Error - no project directory
+// Scenario 8: Single-file mode (no _quarto.yml) - should work, using current directory
 const noProjectDir = join(tempDir, "no-project");
 ensureDirSync(noProjectDir);
 testQuartoCmd(
   "use",
   ["brand", join(fixtureDir, "basic-brand"), "--force"],
   [
-    printsMessage({ level: "ERROR", regex: /Could not find project dir/ }),
+    noErrorsOrWarnings,
+    // Should create _brand/ in the current directory even without _quarto.yml
+    folderExists(join(noProjectDir, "_brand")),
+    fileExists(join(noProjectDir, "_brand", "_brand.yml")),
+    fileExists(join(noProjectDir, "_brand", "logo.png")),
   ],
   {
     setup: () => {
-      // No _quarto.yml created - this should cause an error
+      // No _quarto.yml created - single-file mode should work
       return Promise.resolve();
     },
     cwd: () => noProjectDir,
@@ -347,7 +351,7 @@ testQuartoCmd(
       return Promise.resolve();
     }
   },
-  "quarto use brand - error on no project"
+  "quarto use brand - single-file mode (no _quarto.yml)"
 );
 
 // Scenario 9: Nested directory - overwrite files in subdirectories, remove extra
@@ -650,3 +654,88 @@ testQuartoCmd(
   },
   "quarto use brand - deeply nested directories recursively cleaned up"
 );
+
+// Scenario 15: Brand extension - basic installation
+// Tests that brand extensions are detected and the brand file is renamed to _brand.yml
+const brandExtDir = join(tempDir, "brand-ext");
+ensureDirSync(brandExtDir);
+testQuartoCmd(
+  "use",
+  ["brand", join(fixtureDir, "brand-extension"), "--force"],
+  [
+    noErrorsOrWarnings,
+    folderExists(join(brandExtDir, "_brand")),
+    // brand.yml should be renamed to _brand.yml
+    fileExists(join(brandExtDir, "_brand", "_brand.yml")),
+    // logo.png should be copied
+    fileExists(join(brandExtDir, "_brand", "logo.png")),
+    // _extension.yml should NOT be copied
+    {
+      name: "_extension.yml should not be copied",
+      verify: () => {
+        if (existsSync(join(brandExtDir, "_brand", "_extension.yml"))) {
+          throw new Error("_extension.yml should not be copied from brand extension");
+        }
+        return Promise.resolve();
+      }
+    },
+    // Verify the content is correct (from brand.yml, not some other file)
+    {
+      name: "_brand.yml should contain brand extension content",
+      verify: () => {
+        const content = Deno.readTextFileSync(join(brandExtDir, "_brand", "_brand.yml"));
+        if (!content.includes("Test Brand Extension")) {
+          throw new Error("_brand.yml should contain content from brand.yml");
+        }
+        return Promise.resolve();
+      }
+    },
+  ],
+  {
+    setup: () => {
+      Deno.writeTextFileSync(join(brandExtDir, "_quarto.yml"), "project:\n  type: default\n");
+      return Promise.resolve();
+    },
+    cwd: () => brandExtDir,
+    teardown: () => {
+      try { Deno.removeSync(brandExtDir, { recursive: true }); } catch { /* ignore */ }
+      return Promise.resolve();
+    }
+  },
+  "quarto use brand - brand extension installation"
+);
+
+// Scenario 16: Brand extension - dry-run shows correct file names
+const brandExtDryRunDir = join(tempDir, "brand-ext-dry-run");
+ensureDirSync(brandExtDryRunDir);
+testQuartoCmd(
+  "use",
+  ["brand", join(fixtureDir, "brand-extension"), "--dry-run"],
+  [
+    noErrorsOrWarnings,
+    // Should show _brand.yml (renamed from brand.yml), not brand.yml
+    filesInSections({ create: ["_brand.yml", "logo.png"] }, true),
+    // _brand directory should not exist in dry-run mode
+    {
+      name: "_brand directory should not exist in dry-run mode",
+      verify: () => {
+        if (existsSync(join(brandExtDryRunDir, "_brand"))) {
+          throw new Error("_brand directory should not exist in dry-run mode");
+        }
+        return Promise.resolve();
+      }
+    }
+  ],
+  {
+    setup: () => {
+      Deno.writeTextFileSync(join(brandExtDryRunDir, "_quarto.yml"), "project:\n  type: default\n");
+      return Promise.resolve();
+    },
+    cwd: () => brandExtDryRunDir,
+    teardown: () => {
+      try { Deno.removeSync(brandExtDryRunDir, { recursive: true }); } catch { /* ignore */ }
+      return Promise.resolve();
+    }
+  },
+  "quarto use brand - brand extension dry-run shows renamed file"
+);