diff --git a/config/app.php b/config/app.php
index a6532276..c6905ec9 100644
--- a/config/app.php
+++ b/config/app.php
@@ -4,6 +4,20 @@ use Illuminate\Support\Facades\Facade;
 
 return [
 
+    /*
+    |--------------------------------------------------------------------------
+    | Application Timezone
+    |--------------------------------------------------------------------------
+    |
+    | The default timezone for date and date-time functions. Laravel's own
+    | fallback is the literal string 'UTC' rather than an env() lookup, so
+    | without this key APP_TIMEZONE has no effect at all and scheduled tasks
+    | and recurring invoices always run on UTC.
+    |
+    */
+
+    'timezone' => env('APP_TIMEZONE', 'UTC'),
+
     /*
     |--------------------------------------------------------------------------
     | Class Aliases
diff --git a/docker/production/inject.sh b/docker/production/inject.sh
index 3119172e..20658249 100644
--- a/docker/production/inject.sh
+++ b/docker/production/inject.sh
@@ -48,8 +48,13 @@ elif [ "$DB_PASSWORD_FILE" != '' ]; then
   value=$(<$DB_PASSWORD_FILE)
    replace_or_insert "DB_PASSWORD" "$value"
 fi
-if [ "$TIMEZONE" != '' ]; then
-   replace_or_insert "TIMEZONE" "$TIMEZONE"
+# Laravel reads APP_TIMEZONE. This previously wrote a bare TIMEZONE key, which
+# nothing consumed, so setting the variable silently did nothing. Accept both
+# names so existing compose files keep working.
+if [ "$APP_TIMEZONE" != '' ]; then
+   replace_or_insert "APP_TIMEZONE" "$APP_TIMEZONE"
+elif [ "$TIMEZONE" != '' ]; then
+   replace_or_insert "APP_TIMEZONE" "$TIMEZONE"
 fi
 if [ "$CACHE_STORE" != '' ]; then
    replace_or_insert "CACHE_STORE" "$CACHE_STORE"