diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7a0bc47a..76fa3802 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -43,6 +43,8 @@
   (https://codeberg.org/dnkl/foot/issues/79).
 * Implement XTSAVE/XTRESTORE escape sequences, `CSI ? Ps s` and `CSI ?
   Ps r` (https://codeberg.org/dnkl/foot/issues/91).
+* `$COLORTERM` is now set to `truecolor` at startup, to indicate
+  support for 24-bit RGB colors.
 
 
 ### Deprecated
diff --git a/slave.c b/slave.c
index a6667507..b104a8d7 100644
--- a/slave.c
+++ b/slave.c
@@ -287,6 +287,7 @@ slave_spawn(int ptmx, int argc, const char *cwd, char *const *argv,
         }
 
         setenv("TERM", term_env, 1);
+        setenv("COLORTERM", "truecolor", 1);
 
         char **_shell_argv = NULL;
         char **shell_argv = NULL;