Index: trunk/src/org/openstreetmap/josm/tools/Tag2Link.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/Tag2Link.java	(revision 16771)
+++ trunk/src/org/openstreetmap/josm/tools/Tag2Link.java	(revision 16774)
@@ -156,5 +156,6 @@
         if (keyMatcher.matches() && valueMatcher.matches()) {
             final String lang = Utils.firstNotEmptyString("en", keyMatcher.group("lang"), valueMatcher.group("lang"));
-            linkConsumer.acceptLink(tr("View Wikipedia article"), "https://" + lang + ".wikipedia.org/wiki/" + valueMatcher.group("article"));
+            final String url = "https://" + lang + ".wikipedia.org/wiki/" + valueMatcher.group("article").replace(' ', '_');
+            linkConsumer.acceptLink(tr("View Wikipedia article"), url);
         }
         if (key.matches("(.*:)?wikidata")) {