diff --git a/data-url/src/forgiving_base64.rs b/data-url/src/forgiving_base64.rs
index 5cb1bc43c..ed713d8e1 100644
--- a/data-url/src/forgiving_base64.rs
+++ b/data-url/src/forgiving_base64.rs
@@ -21,6 +21,9 @@ impl fmt::Display for InvalidBase64 {
     }
 }
 
+#[cfg(feature = "std")]
+impl std::error::Error for InvalidBase64 {}
+
 #[derive(Debug)]
 enum InvalidBase64Details {
     UnexpectedSymbol(u8),