diff --git a/tests/morphology/test_morphology_pickle.py b/tests/morphology/test_morphology_pickle.py
index f1b5bcd4c..d8cb88370 100644
--- a/tests/morphology/test_morphology_pickle.py
+++ b/tests/morphology/test_morphology_pickle.py
@@ -1,7 +1,7 @@
 import pytest
 
 import pickle
-import StringIO
+import io
 
 
 from spacy.morphology import Morphology
@@ -12,6 +12,6 @@ from spacy.strings import StringStore
 def test_pickle():
     morphology = Morphology(StringStore(), {}, Lemmatizer({}, {}, {})) 
 
-    file_ = StringIO.StringIO()
+    file_ = io.BytesIO()
     pickle.dump(morphology, file_)
 
diff --git a/tests/parser/test_parser_pickle.py b/tests/parser/test_parser_pickle.py
index b1b768650..547bf4a24 100644
--- a/tests/parser/test_parser_pickle.py
+++ b/tests/parser/test_parser_pickle.py
@@ -2,12 +2,13 @@ import pytest
 
 import pickle
 import cloudpickle
-import StringIO
+
+import io
 
 
 @pytest.mark.models
 def test_pickle(EN):
-    file_ = StringIO.StringIO()
+    file_ = io.BytesIO()
     cloudpickle.dump(EN.parser, file_)
 
     file_.seek(0)
diff --git a/tests/test_pickle.py b/tests/test_pickle.py
index 02d908b0d..a3d54c627 100644
--- a/tests/test_pickle.py
+++ b/tests/test_pickle.py
@@ -1,12 +1,12 @@
 import pytest
-import StringIO
+import io
 import cloudpickle
 import pickle
 
 
 @pytest.mark.models
 def test_pickle_english(EN):
-    file_ = StringIO.StringIO()
+    file_ = io.BytesIO()
     cloudpickle.dump(EN, file_)
 
     file_.seek(0)
diff --git a/tests/vocab/test_vocab.py b/tests/vocab/test_vocab.py
index 5981f30e7..eedf579de 100644
--- a/tests/vocab/test_vocab.py
+++ b/tests/vocab/test_vocab.py
@@ -1,6 +1,6 @@
 from __future__ import unicode_literals
 import pytest
-import StringIO
+import io
 import cloudpickle
 import pickle
 
@@ -46,7 +46,7 @@ def test_symbols(en_vocab):
     
 
 def test_pickle_vocab(en_vocab):
-    file_ = StringIO.StringIO()
+    file_ = io.BytesIO()
     cloudpickle.dump(en_vocab, file_)
 
     file_.seek(0)