diff --git a/addons/mail/static/src/less/chat_window.less b/addons/mail/static/src/less/chat_window.less
index 79e7ae3f298120b5d1d07407f585505afd418b79..a02fd81bb0d97a75d28e50b206698b7ee1c9cad0 100644
--- a/addons/mail/static/src/less/chat_window.less
+++ b/addons/mail/static/src/less/chat_window.less
@@ -78,6 +78,7 @@
     .o_mail_thread {
         .o-flex(1, 1, auto);
         overflow: auto;
+        -webkit-overflow-scrolling: touch; // smooth scrolling in iOS app (Safari)
         .o_thread_date_separator {
             margin: 0px 0px 15px 0px;
             .o_thread_date {
diff --git a/addons/mail/static/src/less/client_action.less b/addons/mail/static/src/less/client_action.less
index 9687637589676c804a52d06e7c530065dce9c7b4..0dd284afb9023ed84635ad8c5a2b528c27f1fcf3 100644
--- a/addons/mail/static/src/less/client_action.less
+++ b/addons/mail/static/src/less/client_action.less
@@ -129,6 +129,7 @@
             .o-flex(1, 0, 0);
             overflow: auto;
             padding: 0 0 15px 0;
+            -webkit-overflow-scrolling: touch; // smooth scrolling in iOS app (Safari)
 
             .o_chat_help_message {
                 padding: 25px 0;