diff --git a/lettre_email/src/lib.rs b/lettre_email/src/lib.rs
index c170e1c..73befae 100644
--- a/lettre_email/src/lib.rs
+++ b/lettre_email/src/lib.rs
@@ -662,7 +662,7 @@ impl EmailBuilder {
     pub fn set_html<S: Into<String>>(&mut self, body: S) {
         let html = PartBuilder::new()
             .body(body)
-            .header(("Content-Type", format!("{}", mime::TEXT_HTML).as_ref()))
+            .header(("Content-Type", format!("{}", mime::TEXT_HTML_UTF_8).as_ref()))
             .build();
         self.add_child(html);
     }
@@ -696,7 +696,7 @@ impl EmailBuilder {
 
         let html = PartBuilder::new()
             .body(body_html)
-            .header(("Content-Type", format!("{}", mime::TEXT_HTML).as_ref()))
+            .header(("Content-Type", format!("{}", mime::TEXT_HTML_UTF_8).as_ref()))
             .build();
 
         alternate.add_child(text);