diff --git a/.envrc b/.envrc
index e0b42ec667..da39298261 100644
--- a/.envrc
+++ b/.envrc
@@ -24,3 +24,7 @@ PATH_add "./.env/bin"
 
 # allow local .envrc overrides
 [[ -f .envrc.local ]] && source_env .envrc.local
+
+# Locale
+export LC_ALL=en_US.UTF-8
+export LANG=en_US.UTF-8
diff --git a/Makefile b/Makefile
index 38a20a7a59..f32542ca2d 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,4 @@
 SHELL                 := /usr/bin/env bash
-LANG                  := en_US.UTF-8
 DOCKER_USER           ?= quay.io/wire
 # kubernetes namespace for running integration tests
 NAMESPACE             ?= test-$(USER)
diff --git a/changelog.d/5-internal/nix-locale-archive b/changelog.d/5-internal/nix-locale-archive
new file mode 100644
index 0000000000..5cbc0d3b44
--- /dev/null
+++ b/changelog.d/5-internal/nix-locale-archive
@@ -0,0 +1 @@
+Fix locale variables in Nix and .envrc
diff --git a/nix/default.nix b/nix/default.nix
index 9d985d08dd..28c3925e49 100644
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -117,6 +117,7 @@ let
     # This gets sourced by direnv. Set NIX_PATH, so `nix-shell` uses the same nixpkgs as here.
     text = ''
       export NIX_PATH=nixpkgs=${toString pkgs.path}
+      export LOCALE_ARCHIVE=${pkgs.glibcLocales}/lib/locale/locale-archive
     '';
   };
 
diff --git a/tools/ormolu.sh b/tools/ormolu.sh
index e34fddf301..924cd93a4b 100755
--- a/tools/ormolu.sh
+++ b/tools/ormolu.sh
@@ -67,11 +67,6 @@ if [ -t 1 ]; then
     : ${ORMOLU_CONDENSE_OUTPUT:=1}
 fi
 
-# https://github.com/tweag/ormolu/issues/38
-# https://gitlab.haskell.org/ghc/ghc/-/issues/17755
-export LANG=C.UTF-8
-export LC_ALL=C.UTF-8
-
 for hsfile in $(git ls-files | grep '\.hsc\?$'); do
     FAILED=0