diff --git a/CHANGELOG.md b/CHANGELOG.md
index 09877189..403df07b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@ and this project adheres to
 
 ## [unreleased]
 
+## Added
+
+- Define `CLICOLOR_FORCE=1` in CI runs.
+
 ## [2.0.6]
 
 ### Added
diff --git a/dist/index.js b/dist/index.js
index eb48bb7d..33101d58 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -112995,6 +112995,7 @@ async function installer() {
         lib_core.exportVariable("DUNE_CACHE", "enabled");
         lib_core.exportVariable("DUNE_CACHE_TRANSPORT", "direct");
     }
+    lib_core.exportVariable("CLICOLOR_FORCE", "1");
     const fnames = await getOpamLocalPackages();
     if (fnames.length > 0) {
         if (OPAM_PIN) {
diff --git a/src/setup-ocaml/installer.ts b/src/setup-ocaml/installer.ts
index f2530bf2..fe201f97 100644
--- a/src/setup-ocaml/installer.ts
+++ b/src/setup-ocaml/installer.ts
@@ -142,6 +142,7 @@ export async function installer(): Promise<void> {
     core.exportVariable("DUNE_CACHE", "enabled");
     core.exportVariable("DUNE_CACHE_TRANSPORT", "direct");
   }
+  core.exportVariable("CLICOLOR_FORCE", "1");
   const fnames = await getOpamLocalPackages();
   if (fnames.length > 0) {
     if (OPAM_PIN) {