diff --git a/.tmux/tmux.conf b/.tmux/tmux.conf
index 9c50b63..17f732e 100644
--- a/.tmux/tmux.conf
+++ b/.tmux/tmux.conf
@@ -15,6 +15,9 @@ setw -g allow-rename on
 setw -g automatic-rename on
 setw -g aggressive-resize off
 
+set -as terminal-overrides ',*:Smulx=\E[4::%p1%dm'  # undercurl support
+set -as terminal-overrides ',*:Setulc=\E[58::2::%p1%{65536}%/%d::%p1%{256}%/%{255}%&%d::%p1%{255}%&%d%;m'  # underscore colors - needs tmux-3.0
+
 # Change prefix key to C-a, easier to type, same as "screen"
 unbind C-b
 set -g prefix C-a