diff --git a/src/PackageJsonSynchronizer.php b/src/PackageJsonSynchronizer.php
index 698894c5b..5daec3ba8 100644
--- a/src/PackageJsonSynchronizer.php
+++ b/src/PackageJsonSynchronizer.php
@@ -104,7 +104,7 @@ private function removeObsoletePackageJsonLinks(): bool
 
         foreach (['dependencies' => $jsDependencies, 'devDependencies' => $jsDevDependencies] as $key => $packages) {
             foreach ($packages as $name => $version) {
-                if ('@' !== $name[0] || 0 !== strpos($version, 'file:'.$this->vendorDir.'/') || false === strpos($version, '/assets')) {
+                if ('@' !== $name[0] || !str_starts_with($version, 'file:'.$this->vendorDir.'/') || !str_contains($version, '/assets')) {
                     continue;
                 }
                 if (file_exists($this->rootDir.'/'.substr($version, 5).'/package.json')) {
@@ -149,20 +149,36 @@ private function resolveImportMapPackages($phpPackage): array
         $dependencies = [];
 
         foreach ($packageJson->read()['symfony']['importmap'] ?? [] as $importMapName => $constraintConfig) {
-            if (\is_array($constraintConfig)) {
-                $constraint = $constraintConfig['version'] ?? [];
-                $package = $constraintConfig['package'] ?? $importMapName;
-            } else {
+            if (\is_string($constraintConfig)) {
+                // Matches string constraint, like "^3.0" or "path:%PACKAGE%/script.js"
                 $constraint = $constraintConfig;
                 $package = $importMapName;
+                $entrypoint = false;
+            } elseif (\is_array($constraintConfig)) {
+                // Matches array constraint, like {"version":"^3.0"} or {"version":"path:%PACKAGE%/script.js","entrypoint":true}
+                // Note that non-path assets can't be entrypoint
+                $constraint = $constraintConfig['version'] ?? '';
+                $package = $constraintConfig['package'] ?? $importMapName;
+                $entrypoint = $constraintConfig['entrypoint'] ?? false;
+            } else {
+                throw new \InvalidArgumentException(\sprintf('Invalid constraint config for key "%s": "%s" given, array or string expected.', $importMapName, var_export($constraintConfig, true)));
             }
 
-            if (0 === strpos($constraint, 'path:')) {
+            // When "$constraintConfig" matches one of the following cases:
+            // - "entrypoint:%PACKAGE%/script.js"
+            // - {"version": "entrypoint:%PACKAGE%/script.js"}
+            if (str_starts_with($constraint, 'entrypoint:')) {
+                $entrypoint = true;
+                $constraint = substr_replace($constraint, 'path:', 0, \strlen('entrypoint:'));
+            }
+
+            if (str_starts_with($constraint, 'path:')) {
                 $path = substr($constraint, 5);
                 $path = str_replace('%PACKAGE%', \dirname($packageJson->getPath()), $path);
 
                 $dependencies[$importMapName] = [
                     'path' => $path,
+                    'entrypoint' => $entrypoint,
                 ];
 
                 continue;
@@ -239,7 +255,7 @@ private function shouldUpdateConstraint(string $existingConstraint, string $cons
     }
 
     /**
-     * @param array<string, array{path?: string, package?: string, version?: string}> $importMapEntries
+     * @param array<string, array{path?: string, package?: string, version?: string, entrypoint?: bool}> $importMapEntries
      */
     private function updateImportMap(array $importMapEntries): void
     {
@@ -264,11 +280,15 @@ private function updateImportMap(array $importMapEntries): void
                     continue;
                 }
 
-                $this->io->writeError(sprintf('Updating package <comment>%s</> from <info>%s</> to <info>%s</>.', $name, $version, $versionConstraint));
+                $this->io->writeError(\sprintf('Updating package <comment>%s</> from <info>%s</> to <info>%s</>.', $name, $version, $versionConstraint));
             }
 
             if (isset($importMapEntry['path'])) {
                 $arguments = [$name, '--path='.$importMapEntry['path']];
+                if (isset($importMapEntry['entrypoint']) && true === $importMapEntry['entrypoint']) {
+                    $arguments[] = '--entrypoint';
+                }
+
                 $this->scriptExecutor->execute(
                     'symfony-cmd',
                     'importmap:require',
@@ -293,7 +313,7 @@ private function updateImportMap(array $importMapEntries): void
                 continue;
             }
 
-            throw new \InvalidArgumentException(sprintf('Invalid importmap entry: "%s".', var_export($importMapEntry, true)));
+            throw new \InvalidArgumentException(\sprintf('Invalid importmap entry: "%s".', var_export($importMapEntry, true)));
         }
     }
 
diff --git a/tests/Fixtures/packageJson/vendor/symfony/importmap-invalid-constraint-package/assets/package.json b/tests/Fixtures/packageJson/vendor/symfony/importmap-invalid-constraint-package/assets/package.json
new file mode 100644
index 000000000..ca57c76dc
--- /dev/null
+++ b/tests/Fixtures/packageJson/vendor/symfony/importmap-invalid-constraint-package/assets/package.json
@@ -0,0 +1,7 @@
+{
+    "symfony": {
+        "importmap": {
+            "@symfony/test": true
+        }
+    }
+}
diff --git a/tests/Fixtures/packageJson/vendor/symfony/new-package/assets/package.json b/tests/Fixtures/packageJson/vendor/symfony/new-package/assets/package.json
index e4003ea6c..419528379 100644
--- a/tests/Fixtures/packageJson/vendor/symfony/new-package/assets/package.json
+++ b/tests/Fixtures/packageJson/vendor/symfony/new-package/assets/package.json
@@ -14,6 +14,11 @@
             "@hotcake/foo": "^1.9.0",
             "@symfony/new-package": {
                 "version": "path:%PACKAGE%/dist/loader.js"
+            },
+            "@symfony/new-package/entry.js": "entrypoint:%PACKAGE%/entry.js",
+            "@symfony/new-package/entry2.js": {
+                "version": "path:%PACKAGE%/entry2.js",
+                "entrypoint": true
             }
         }
     },
diff --git a/tests/PackageJsonSynchronizerTest.php b/tests/PackageJsonSynchronizerTest.php
index 7e6b27c0d..702a3881c 100644
--- a/tests/PackageJsonSynchronizerTest.php
+++ b/tests/PackageJsonSynchronizerTest.php
@@ -323,11 +323,16 @@ public function testSynchronizeAssetMapperNewPackage()
         file_put_contents($this->tempDir.'/importmap.php', '<?php return [];');
 
         $fileModulePath = $this->tempDir.'/vendor/symfony/new-package/assets/dist/loader.js';
-        $this->scriptExecutor->expects($this->exactly(2))
+        $entrypointPath = $this->tempDir.'/vendor/symfony/new-package/assets/entry.js';
+        $secondEntrypointPath = $this->tempDir.'/vendor/symfony/new-package/assets/entry2.js';
+
+        $this->scriptExecutor->expects($this->exactly(4))
             ->method('execute')
             ->withConsecutive(
                 ['symfony-cmd', 'importmap:require', ['@hotcake/foo@^1.9.0']],
-                ['symfony-cmd', 'importmap:require', ['@symfony/new-package', '--path='.$fileModulePath]]
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package', '--path='.$fileModulePath]],
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package/entry.js', '--path='.$entrypointPath, '--entrypoint']],
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package/entry2.js', '--path='.$secondEntrypointPath, '--entrypoint']],
             );
 
         $this->synchronizer->synchronize([
@@ -396,14 +401,19 @@ public function testSynchronizeAssetMapperUpgradesPackageIfNeeded()
                 'version' => '1.8.0',
             ],
         ];
-        file_put_contents($this->tempDir.'/importmap.php', sprintf('<?php return %s;', var_export($importMap, true)));
+        file_put_contents($this->tempDir.'/importmap.php', \sprintf('<?php return %s;', var_export($importMap, true)));
 
         $fileModulePath = $this->tempDir.'/vendor/symfony/new-package/assets/dist/loader.js';
-        $this->scriptExecutor->expects($this->exactly(2))
+        $entrypointPath = $this->tempDir.'/vendor/symfony/new-package/assets/entry.js';
+        $secondEntrypointPath = $this->tempDir.'/vendor/symfony/new-package/assets/entry2.js';
+
+        $this->scriptExecutor->expects($this->exactly(4))
             ->method('execute')
             ->withConsecutive(
                 ['symfony-cmd', 'importmap:require', ['@hotcake/foo@^1.9.0']],
-                ['symfony-cmd', 'importmap:require', ['@symfony/new-package', '--path='.$fileModulePath]]
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package', '--path='.$fileModulePath]],
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package/entry.js', '--path='.$entrypointPath, '--entrypoint']],
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package/entry2.js', '--path='.$secondEntrypointPath, '--entrypoint']]
             );
 
         $this->synchronizer->synchronize([
@@ -421,14 +431,21 @@ public function testSynchronizeAssetMapperSkipsUpgradeIfAlreadySatisfied()
                 // constraint in package.json is ^1.9.0
                 'version' => '1.9.1',
             ],
+            '@symfony/new-package/entry2.js' => [
+                'path' => './vendor/symfony/new-package/assets/entry2.js',
+                'entrypoint' => true,
+            ],
         ];
-        file_put_contents($this->tempDir.'/importmap.php', sprintf('<?php return %s;', var_export($importMap, true)));
+        file_put_contents($this->tempDir.'/importmap.php', \sprintf('<?php return %s;', var_export($importMap, true)));
 
         $fileModulePath = $this->tempDir.'/vendor/symfony/new-package/assets/dist/loader.js';
-        $this->scriptExecutor->expects($this->once())
+        $entrypointPath = $this->tempDir.'/vendor/symfony/new-package/assets/entry.js';
+
+        $this->scriptExecutor->expects($this->exactly(2))
             ->method('execute')
             ->withConsecutive(
-                ['symfony-cmd', 'importmap:require', ['@symfony/new-package', '--path='.$fileModulePath]]
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package', '--path='.$fileModulePath]],
+                ['symfony-cmd', 'importmap:require', ['@symfony/new-package/entry.js', '--path='.$entrypointPath, '--entrypoint']],
             );
 
         $this->synchronizer->synchronize([
@@ -438,4 +455,19 @@ public function testSynchronizeAssetMapperSkipsUpgradeIfAlreadySatisfied()
             ],
         ]);
     }
+
+    public function testExceptionWhenInvalidImportMapConstraint()
+    {
+        file_put_contents($this->tempDir.'/importmap.php', '<?php return [];');
+
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid constraint config for key "@symfony/test": "true" given, array or string expected.');
+
+        $this->synchronizer->synchronize([
+            [
+                'name' => 'symfony/importmap-invalid-constraint-package',
+                'keywords' => ['symfony-ux'],
+            ],
+        ]);
+    }
 }