diff --git a/.github/workflows/alpine.dockerfile b/.github/workflows/alpine.dockerfile
new file mode 100644
index 0000000..1c5cfc9
--- /dev/null
+++ b/.github/workflows/alpine.dockerfile
@@ -0,0 +1,3 @@
+ARG PHP_VERSION
+FROM php:${PHP_VERSION}-cli-alpine
+COPY . .
diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index 4bc9a92..9b8252d 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -60,3 +60,15 @@ jobs:
 
       - name: "Tests"
         run: "vendor/bin/phpunit"
+
+      - name: "Build Alpine image"
+        if: ${{ matrix.operating-system == 'ubuntu-latest' }}
+        run: docker build
+          --file .github/workflows/alpine.dockerfile
+          --build-arg PHP_VERSION=${{ matrix.php-version }}
+          --tag testenv
+          .
+
+      - name: "Test under Alpine"
+        if: ${{ matrix.operating-system == 'ubuntu-latest' }}
+        run: docker run testenv vendor/bin/phpunit
diff --git a/src/Iterator/GlobIterator.php b/src/Iterator/GlobIterator.php
index e88bbeb..2ef80f8 100644
--- a/src/Iterator/GlobIterator.php
+++ b/src/Iterator/GlobIterator.php
@@ -52,7 +52,8 @@ public function __construct($glob, $flags = 0)
                 // glob() does not support [^...] on Windows
                 ('\\' !== DIRECTORY_SEPARATOR || false === strpos($glob, '[^'))
             ) {
-                $results = glob($glob, GLOB_BRACE);
+                // GLOB_BRACE is not available in some environments.
+                $results = glob($glob, defined('GLOB_BRACE') ? GLOB_BRACE : 0);
 
                 // $results may be empty or false if $glob is invalid
                 if (empty($results)) {