diff --git a/click_repl/globals_.py b/click_repl/globals_.py
index 3e1f49b..cc4586a 100644
--- a/click_repl/globals_.py
+++ b/click_repl/globals_.py
@@ -9,7 +9,7 @@
     from .core import ReplContext
 
 
-ISATTY = sys.stdin.isatty()
+ISATTY = sys.stdin is not None and sys.stdin.isatty()
 
 
 @overload
diff --git a/tests/test_import.py b/tests/test_import.py
new file mode 100644
index 0000000..431f5a6
--- /dev/null
+++ b/tests/test_import.py
@@ -0,0 +1,21 @@
+"""Importing the package must work without an attached standard input."""
+
+import os
+import subprocess
+import sys
+
+
+def test_import_without_stdin():
+    # Closing fd 0 causes Python to expose sys.stdin as None. Test in a
+    # child so the test runner's own input stream remains untouched.
+    if os.name == "nt":
+        code = "import sys; sys.stdin = None; import click_repl"
+        result = subprocess.run([sys.executable, "-c", code], capture_output=True)
+    else:
+        result = subprocess.run(
+            [sys.executable, "-c", "import sys; assert sys.stdin is None; "
+             "import click_repl"],
+            capture_output=True,
+            preexec_fn=lambda: os.close(0),
+        )
+    assert result.returncode == 0, result.stderr.decode(errors="replace")