diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index dac30cbf400..a286c126c9e 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -2505,6 +2505,8 @@ def test_io_after_close(self):
             self.assertRaises(ValueError, f.read)
             if hasattr(f, "read1"):
                 self.assertRaises(ValueError, f.read1, 1024)
+            if hasattr(f, "readall"):
+                self.assertRaises(ValueError, f.readall)
             if hasattr(f, "readinto"):
                 self.assertRaises(ValueError, f.readinto, bytearray(1024))
             self.assertRaises(ValueError, f.readline)
diff --git a/Misc/NEWS b/Misc/NEWS
index 8d19f7a2c14..05fc1b750b3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -731,6 +731,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError
+  if the file is closed.
+
 - Issue #10916: mmap should not segfault when a file is mapped using 0 as length
   and a non-zero offset, and an attempt to read past the end of file is made
   (IndexError is raised instead).  Patch by Ross Lagerwall.
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 1aa5ee992d7..141b6dece1b 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -583,6 +583,8 @@ fileio_readall(fileio *self)
     Py_ssize_t total = 0;
     int n;
 
+    if (self->fd < 0)
+        return err_closed();
     if (!_PyVerify_fd(self->fd))
         return PyErr_SetFromErrno(PyExc_IOError);