diff --git a/picard.wdl b/picard.wdl
index 87243a10b64ac79ceccd0115f1b887c5b1983745..4a73bc313da353e168832f3116c36ad8a54a0bcc 100644
--- a/picard.wdl
+++ b/picard.wdl
@@ -403,7 +403,7 @@ task SortVcf {
         SortVcf \
         I=~{sep=" I=" vcfFiles} \
         ~{"SEQUENCE_DICTIONARY=" + sequenceDict} \
-        O=outputVcf
+        O=~{outputVcf}
     }
 
     output {