diff --git a/spacy/gold.pyx b/spacy/gold.pyx
index 91204f671..756e6a5fa 100644
--- a/spacy/gold.pyx
+++ b/spacy/gold.pyx
@@ -456,12 +456,16 @@ cdef class GoldParse:
         if deps is None:
             deps = [None for _ in doc]
         if entities is None:
-            entities = [None for _ in doc]
+            entities = ['-' for _ in doc]
         elif len(entities) == 0:
             entities = ['O' for _ in doc]
-        elif not isinstance(entities[0], basestring):
-            # Assume we have entities specified by character offset.
-            entities = biluo_tags_from_offsets(doc, entities)
+        else:
+            # Translate the None values to '-', to make processing easier.
+            # See Issue #2603
+            entities = [(ent if ent is not None else '-') for ent in entities]
+            if not isinstance(entities[0], basestring):
+                # Assume we have entities specified by character offset.
+                entities = biluo_tags_from_offsets(doc, entities)
 
         self.mem = Pool()
         self.loss = 0
diff --git a/spacy/syntax/ner.pyx b/spacy/syntax/ner.pyx
index 7a1d34c00..b43a879d4 100644
--- a/spacy/syntax/ner.pyx
+++ b/spacy/syntax/ner.pyx
@@ -141,7 +141,7 @@ cdef class BiluoPushDown(TransitionSystem):
 
     cdef Transition lookup_transition(self, object name) except *:
         cdef attr_t label
-        if name == '-' or name is None:
+        if name == '-' or name == '' or name is None:
             return Transition(clas=0, move=MISSING, label=0, score=0)
         elif name == '!O':
             return Transition(clas=0, move=ISNT, label=0, score=0)
diff --git a/spacy/tests/test_gold.py b/spacy/tests/test_gold.py
index 30dd2e6c6..21024312c 100644
--- a/spacy/tests/test_gold.py
+++ b/spacy/tests/test_gold.py
@@ -2,7 +2,7 @@
 from __future__ import unicode_literals
 
 from spacy.gold import biluo_tags_from_offsets, offsets_from_biluo_tags
-from spacy.gold import spans_from_biluo_tags
+from spacy.gold import spans_from_biluo_tags, GoldParse
 from spacy.tokens import Doc
 
 
@@ -62,3 +62,9 @@ def test_biluo_spans(en_tokenizer):
     assert spans[0].label_ == "LOC"
     assert spans[1].text == "London"
     assert spans[1].label_ == "GPE"
+
+def test_gold_ner_missing_tags(en_tokenizer):
+    doc = en_tokenizer("I flew to Silicon Valley via London.")
+    biluo_tags = [None, "O", "O", "B-LOC", "L-LOC", "O", "U-GPE", "O"]
+    gold = GoldParse(doc, entities=biluo_tags)
+ 
diff --git a/website/docs/api/goldparse.md b/website/docs/api/goldparse.md
index 1f71c5d58..82a850dbd 100644
--- a/website/docs/api/goldparse.md
+++ b/website/docs/api/goldparse.md
@@ -21,7 +21,7 @@ gradient for those labels will be zero.
 | `tags`      | iterable    | A sequence of strings, representing tag annotations.                                                                                                                                                                      |
 | `heads`     | iterable    | A sequence of integers, representing syntactic head offsets.                                                                                                                                                              |
 | `deps`      | iterable    | A sequence of strings, representing the syntactic relation types.                                                                                                                                                         |
-| `entities`  | iterable    | A sequence of named entity annotations, either as BILUO tag strings, or as `(start_char, end_char, label)` tuples, representing the entity positions.                                                                     |
+| `entities`  | iterable    | A sequence of named entity annotations, either as BILUO tag strings, or as `(start_char, end_char, label)` tuples, representing the entity positions. If BILUO tag strings, you can specify missing values by setting the tag to None. |
 | `cats`      | dict        | Labels for text classification. Each key in the dictionary may be a string or an int, or a `(start_char, end_char, label)` tuple, indicating that the label is applied to only part of the document (usually a sentence). |
 | **RETURNS** | `GoldParse` | The newly constructed object.                                                                                                                                                                                             |