diff --git a/pytools/__init__.py b/pytools/__init__.py
index ec878b57659ff92db73ad5c67361ed8817097007..e7d2306a7b04863dc4405ad37a5c4b11f01a5c82 100644
--- a/pytools/__init__.py
+++ b/pytools/__init__.py
@@ -169,6 +169,11 @@ Backports of newer Python functionality
 
 .. autofunction:: resolve_name
 
+Hashing
+-------
+
+.. autofunction:: unordered_hash
+
 Type Variables Used
 -------------------
 
@@ -2605,6 +2610,37 @@ def resolve_name(name):
 # }}}
 
 
+# {{{ unordered_hash
+
+def unordered_hash(hash_constructor, iterable):
+    """Using a hash algorithm given by the parameter-less constructor
+    *hash_constructor*, return a hash object whose internal state
+    depends on the entries of *iterable*, but not their order. If *hash*
+    is the instance returned by evaluating ``hash_constructor()``, then
+    the each entry *i* of the iterable must permit ``hash.upate(i)`` to
+    succeed. An example of *hash_constructor* is :class:`hashlib.sha256`.
+    ``hash.digest_size`` must also be defined.
+
+    .. warning::
+
+        The construction used in this function is likely not cryptographically
+        secure. Do not use this function in a security-relevant context.
+
+    .. versionadded:: 2021.2
+    """
+    h_int = 0
+    for i in iterable:
+        h_i = hash_constructor()
+        h_i.update(i)
+        h_int = h_int ^ int.from_bytes(h_i.digest(), sys.byteorder)
+
+    h = hash_constructor()
+    h.update(h_int.to_bytes(h.digest_size, sys.byteorder))
+    return h
+
+# }}}
+
+
 def _test():
     import doctest
     doctest.testmod()
diff --git a/test/test_pytools.py b/test/test_pytools.py
index 87b5d3a76d2d76e4a61e8343252e9b81cd7c767c..59cfc92b0fa4f9b1c57117d8ac734f1b706fa6da 100644
--- a/test/test_pytools.py
+++ b/test/test_pytools.py
@@ -370,6 +370,26 @@ def test_tag():
         t4.without_tags(red_ribbon)
 
 
+def test_unordered_hash():
+    import random
+    import hashlib
+
+    lst = [random.randbytes(20) for _ in range(200)]
+    lorig = lst[:]
+    random.shuffle(lst)
+
+    from pytools import unordered_hash
+    assert (unordered_hash(hashlib.sha256, lorig).digest()
+            == unordered_hash(hashlib.sha256, lst).digest())
+    assert (unordered_hash(hashlib.sha256, lorig).digest()
+            == unordered_hash(hashlib.sha256, lorig).digest())
+    assert (unordered_hash(hashlib.sha256, lorig).digest()
+            != unordered_hash(hashlib.sha256, lorig[:-1]).digest())
+    lst[0] = b"aksdjfla;sdfjafd"
+    assert (unordered_hash(hashlib.sha256, lorig).digest()
+            != unordered_hash(hashlib.sha256, lst).digest())
+
+
 if __name__ == "__main__":
     if len(sys.argv) > 1:
         exec(sys.argv[1])