diff --git a/src/cli.ts b/src/cli.ts
index 369530d..23ea7a6 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -1,7 +1,10 @@
 import { createApp } from './app.ts';
+import { registerBuildCommand } from './commands/build.ts';
 
 const program = createApp();
 
+registerBuildCommand(program);
+
 program.parseAsync(process.argv).catch((err) => {
   console.error(err instanceof Error ? err.message : String(err));
   process.exit(1);
diff --git a/src/commands/build.ts b/src/commands/build.ts
new file mode 100644
index 0000000..491c9fd
--- /dev/null
+++ b/src/commands/build.ts
@@ -0,0 +1,54 @@
+import type { Command } from 'commander';
+import { getConfig } from '../config.ts';
+import { runCommand } from '../utils/process.ts';
+import * as output from '../utils/output.ts';
+
+/**
+ * Registers the `build` command with the CLI program.
+ *
+ * @since TBD
+ *
+ * @param {Command} program - The Commander.js program instance.
+ *
+ * @returns {void}
+ */
+export function registerBuildCommand(program: Command): void {
+  program
+    .command('build')
+    .description('Run the build commands.')
+    .option('--dev', 'Run the dev build commands.')
+    .option('--root <dir>', 'Set the root directory for running commands.')
+    .action(async (options: { dev?: boolean; root?: string }) => {
+      const config = getConfig();
+      const buildSteps = config.getBuildCommands(options.dev);
+      const cwd = options.root ?? config.getWorkingDir();
+
+      output.log('Running build steps...');
+
+      for (const step of buildSteps) {
+        let cmd = step;
+        let bailOnFailure = true;
+
+        if (cmd.startsWith('@')) {
+          bailOnFailure = false;
+          cmd = cmd.slice(1);
+        }
+
+        output.section(`> ${cmd}`);
+
+        const result = await runCommand(cmd, {
+          cwd,
+        });
+
+        if (result.exitCode !== 0) {
+          output.error(`[FAIL] Build step failed: ${cmd}`);
+          if (bailOnFailure) {
+            output.error('Exiting...');
+            process.exit(result.exitCode);
+          }
+        }
+      }
+
+      output.success('Build complete.');
+    });
+}
diff --git a/tests/commands/build.test.ts b/tests/commands/build.test.ts
new file mode 100644
index 0000000..1975c9d
--- /dev/null
+++ b/tests/commands/build.test.ts
@@ -0,0 +1,84 @@
+import {
+  runPup,
+  writePuprc,
+  getPuprc,
+  createTempProject,
+  cleanupTempProjects,
+} from '../helpers/setup.js';
+
+describe('build command', () => {
+  let projectDir: string;
+
+  beforeEach(() => {
+    projectDir = createTempProject();
+  });
+
+  afterEach(() => {
+    cleanupTempProjects();
+  });
+
+  it('should run build', async () => {
+    const puprc = getPuprc();
+    puprc.build = ['echo "fake project, yo"'];
+    writePuprc(puprc, projectDir);
+
+    const result = await runPup('build', { cwd: projectDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.output).toContain('fake project, yo');
+  });
+
+  it('should handle no build steps', async () => {
+    const puprc = getPuprc();
+    puprc.build = [];
+    writePuprc(puprc, projectDir);
+
+    const result = await runPup('build', { cwd: projectDir });
+    expect(result.exitCode).toBe(0);
+  });
+
+  it('should succeed with defaults when no .puprc exists (defaults to no build steps)', async () => {
+    const emptyDir = createTempProject();
+    const result = await runPup('build', { cwd: emptyDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.output).toContain('Build complete');
+  });
+
+  it('should pass env vars that are not defined in puprc.env', async () => {
+    const puprc = getPuprc();
+    puprc.build = ['echo "TOKEN=$PUP_TEST_UNIQUE_VAR"'];
+    writePuprc(puprc, projectDir);
+
+    process.env.PUP_TEST_UNIQUE_VAR = 'test-token-12345';
+
+    try {
+      const result = await runPup('build', { cwd: projectDir });
+      expect(result.exitCode).toBe(0);
+      expect(result.output).toContain('TOKEN=test-token-12345');
+    } finally {
+      delete process.env.PUP_TEST_UNIQUE_VAR;
+    }
+  });
+
+  it('should run build in the specified --root directory', async () => {
+    const rootDir = createTempProject();
+
+    const puprc = getPuprc();
+    puprc.build = ['pwd'];
+    writePuprc(puprc, projectDir);
+
+    const result = await runPup(`build --root ${rootDir}`, { cwd: projectDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.output).toContain(rootDir);
+  });
+
+  it('should run build with dev flag', async () => {
+    const puprc = getPuprc();
+    puprc.build = ['echo "production build"'];
+    (puprc as Record<string, unknown>).build_dev = ['echo "dev build"'];
+    writePuprc(puprc, projectDir);
+
+    const result = await runPup('build --dev', { cwd: projectDir });
+    expect(result.exitCode).toBe(0);
+    expect(result.output).toContain('dev build');
+  });
+});