diff --git a/spacy/vocab.pyx b/spacy/vocab.pyx
index 7d51c6c6d..d0df37317 100644
--- a/spacy/vocab.pyx
+++ b/spacy/vocab.pyx
@@ -270,16 +270,25 @@ cdef class Vocab:
     def load_vectors_bz2(self, loc):
         cdef LexemeC* lexeme
         cdef attr_t orth
+        cdef int32_t vec_len = -1
         with bz2.BZ2File(loc, 'r') as file_:
-            for line in file_:
+            for line_num, line in enumerate(file_):
                 pieces = line.split()
                 word_str = pieces.pop(0)
+                if vec_len == -1:
+                    vec_len = len(pieces)
+                elif vec_len != len(pieces):
+                    raise IOError(
+                        "Error loading word vectors: all vectors must be same "
+                        "length. Previous vector was length %d, vector on line %d "
+                        "was length %d." % (vec_len, line_num, len(pieces)))
                 orth = self.strings[word_str]
                 lexeme = <LexemeC*><void*>self.get_by_orth(self.mem, orth)
                 lexeme.repvec = <float*>self.mem.alloc(len(pieces), sizeof(float))
 
                 for i, val_str in enumerate(pieces):
                     lexeme.repvec[i] = float(val_str)
+        return vec_len
 
     def load_vectors_bin(self, loc):
         cdef CFile file_ = CFile(loc, b'rb')