diff --git a/spacy/strings.pyx b/spacy/strings.pyx
index d54dcdf1a..d11936d12 100644
--- a/spacy/strings.pyx
+++ b/spacy/strings.pyx
@@ -118,6 +118,11 @@ cdef class StringStore:
         else:
             raise TypeError(type(string_or_id))
 
+    def __contains__(self, unicode string):
+        cdef hash_t key = hash_string(string)
+        value = <Utf8Str*>self._map.get(key)
+        return True if value is not NULL else False
+
     def __iter__(self):
         cdef int i
         for i in range(self.size):
diff --git a/spacy/tests/vocab/test_vocab.py b/spacy/tests/vocab/test_vocab.py
index 27aea46ff..f62cddf0e 100644
--- a/spacy/tests/vocab/test_vocab.py
+++ b/spacy/tests/vocab/test_vocab.py
@@ -43,6 +43,11 @@ def test_symbols(en_vocab):
     assert en_vocab.strings['LEMMA'] == LEMMA
     assert en_vocab.strings['ORTH'] == ORTH
     assert en_vocab.strings['PROB'] == PROB
+
+
+def test_contains(en_vocab):
+    assert 'Hello' in en_vocab
+    assert 'LKsdjvlsakdvlaksdvlkasjdvljasdlkfvm' not in en_vocab
     
 
 @pytest.mark.xfail
diff --git a/spacy/vocab.pyx b/spacy/vocab.pyx
index 391adfa28..f876bfefb 100644
--- a/spacy/vocab.pyx
+++ b/spacy/vocab.pyx
@@ -172,6 +172,11 @@ cdef class Vocab:
         self._by_orth.set(lex.orth, <void*>lex)
         self.length += 1
 
+    def __contains__(self, unicode string):
+        key = hash_string(string)
+        lex = self._by_hash.get(key)
+        return True if lex is not NULL else False
+
     def __iter__(self):
         cdef attr_t orth
         cdef size_t addr