diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c29a01fae3d831562f39d308584ed45f2fb05ec8..a88e66a71e977f6d54ed0108f06edc98629a4cfe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -83,7 +83,7 @@ jobs:
                 # AK, 2020-12-13
                 rm pytools/mpiwrap.py
 
-                EXTRA_INSTALL="numpy frozendict immutabledict orderedsets constantdict immutables pyrsistent"
+                EXTRA_INSTALL="numpy frozendict immutabledict orderedsets constantdict immutables pyrsistent attrs"
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/build-and-test-py-project.sh
                 . ./build-and-test-py-project.sh
 
diff --git a/pytools/persistent_dict.py b/pytools/persistent_dict.py
index 421e02a1d72fd099fcd20723e7461cba95a9074e..47d2a8c0130f4eaf8a8308c2831b6065c89ffdcd 100644
--- a/pytools/persistent_dict.py
+++ b/pytools/persistent_dict.py
@@ -381,14 +381,14 @@ class KeyBuilder:
             key_hash.update(np.array(key).tobytes())
 
     def update_for_dataclass(self, key_hash, key):
-        self.rec(key_hash, type(key_hash).__name__.encode("utf-8"))
+        self.rec(key_hash, f"{type(key).__qualname__}.{type(key).__name__}")
 
         for fld in dc_fields(key):
             self.rec(key_hash, fld.name)
             self.rec(key_hash, getattr(key, fld.name, None))
 
     def update_for_attrs(self, key_hash, key):
-        self.rec(key_hash, type(key_hash).__name__.encode("utf-8"))
+        self.rec(key_hash, f"{type(key).__qualname__}.{type(key).__name__}")
 
         for fld in attrs.fields(key.__class__):
             self.rec(key_hash, fld.name)
diff --git a/pytools/test/test_persistent_dict.py b/pytools/test/test_persistent_dict.py
index eb22ec65b9e44b26a9fe3a5aa1abe733e413eb40..3c852b1bbbc4ca65edc49be9c50a4a0642995dcd 100644
--- a/pytools/test/test_persistent_dict.py
+++ b/pytools/test/test_persistent_dict.py
@@ -518,6 +518,61 @@ def test_class_hashing():
     assert keyb(TagClass2) != keyb(TagClass2())
 
 
+def test_dataclass_hashing():
+    keyb = KeyBuilder()
+
+    @dataclass
+    class MyDC:
+        name: str
+        value: int
+
+    assert keyb(MyDC("hi", 1)) == \
+        "2ba6363c3b98f1cc2209bd57388368b3efe3074e3764eee30fbcf15946efb802"
+
+    assert keyb(MyDC("hi", 1)) == keyb(MyDC("hi", 1))
+    assert keyb(MyDC("hi", 1)) != keyb(MyDC("hi", 2))
+
+    @dataclass
+    class MyDC2:
+        name: str
+        value: int
+
+    # Class types must be encoded in hash
+    assert keyb(MyDC2("hi", 1)) != keyb(MyDC("hi", 1))
+
+
+def test_attrs_hashing():
+    attrs = pytest.importorskip("attrs")
+
+    keyb = KeyBuilder()
+
+    @attrs.define
+    class MyAttrs:
+        name: str
+        value: int
+
+    assert keyb(MyAttrs("hi", 1)) == \
+        "17f272d114d22c1dc0117354777f2d506b303d90e10840d39fb0eef007252f68"
+
+    assert keyb(MyAttrs("hi", 1)) == keyb(MyAttrs("hi", 1))
+    assert keyb(MyAttrs("hi", 1)) != keyb(MyAttrs("hi", 2))
+
+    @dataclass
+    class MyDC:
+        name: str
+        value: int
+
+    assert keyb(MyDC("hi", 1)) != keyb(MyAttrs("hi", 1))
+
+    @attrs.define
+    class MyAttrs2:
+        name: str
+        value: int
+
+    # Class types must be encoded in hash
+    assert keyb(MyAttrs2("hi", 1)) != keyb(MyAttrs("hi", 1))
+
+
 if __name__ == "__main__":
     if len(sys.argv) > 1:
         exec(sys.argv[1])