diff --git a/bson/json_util.py b/bson/json_util.py
index b9e088943..5498bf044 100644
--- a/bson/json_util.py
+++ b/bson/json_util.py
@@ -666,7 +666,11 @@ def _parse_canonical_regex(doc):
     if len(regex) != 2:
         raise TypeError('Bad $regularExpression must include only "pattern"'
                         'and "options" components: %s' % (doc,))
-    return Regex(regex['pattern'], regex['options'])
+    opts = regex['options']
+    if not isinstance(opts, str):
+        raise TypeError('Bad $regularExpression options, options must be '
+                        'string, was type %s' % (type(opts)))
+    return Regex(regex['pattern'], opts)
 
 
 def _parse_canonical_dbref(doc):
diff --git a/test/bson_corpus/top.json b/test/bson_corpus/top.json
index ce7d4cdf9..fe5be0eae 100644
--- a/test/bson_corpus/top.json
+++ b/test/bson_corpus/top.json
@@ -92,11 +92,11 @@
         },
         {
             "description": "Bad $regularExpression (pattern is number, not string)",
-            "string": "{\"x\" : {\"$regularExpression\" : { \"pattern\": 42, \"$options\" : \"\"}}}"
+            "string": "{\"x\" : {\"$regularExpression\" : { \"pattern\": 42, \"options\" : \"\"}}}"
         },
         {
             "description": "Bad $regularExpression (options are number, not string)",
-            "string": "{\"x\" : {\"$regularExpression\" : { \"pattern\": \"a\", \"$options\" : 0}}}"
+            "string": "{\"x\" : {\"$regularExpression\" : { \"pattern\": \"a\", \"options\" : 0}}}"
         },
         {
             "description" : "Bad $regularExpression (missing pattern field)",