diff --git a/templates/blog/post.html b/templates/blog/post.html
index c276ba3b..cddd2edc 100644
--- a/templates/blog/post.html
+++ b/templates/blog/post.html
@@ -9,7 +9,7 @@
     "@type": "BlogPosting",
     "headline": "{{.Title}}",
     "datePublished": "{{.Published.Format "2006-01-02T15:04:05Z07:00"}}",
-    "dateModified": "{{.Modified.Format "2006-01-02T15:04:05Z07:00"}}",
+    {{if not .Modified.IsZero}}"dateModified": "{{.Modified.Format "2006-01-02T15:04:05Z07:00"}}",{{end}}
     {{if .Image}}
         "image": [
             {{range .Image}}
diff --git a/templates/default.html b/templates/default.html
index ccbdef8d..664786fe 100644
--- a/templates/default.html
+++ b/templates/default.html
@@ -9,7 +9,7 @@
     "@type": "Article",
     "headline": "{{.Title}}",
     "datePublished": "{{.Published.Format "2006-01-02T15:04:05Z07:00"}}",
-    "dateModified": "{{.Modified.Format "2006-01-02T15:04:05Z07:00"}}",
+    {{if not .Modified.IsZero}}"dateModified": "{{.Modified.Format "2006-01-02T15:04:05Z07:00"}}",{{end}}
     {{if .Image}}
         "image": [
             {{range .Image}}