diff --git a/ament_package/template/prefix_level/_local_setup_util.py b/ament_package/template/prefix_level/_local_setup_util.py
index c0ea86d..d290ac0 100644
--- a/ament_package/template/prefix_level/_local_setup_util.py
+++ b/ament_package/template/prefix_level/_local_setup_util.py
@@ -54,8 +54,9 @@ def main(argv=sys.argv[1:]):  # noqa: D103
         FORMAT_STR_USE_ENV_VAR = '%{name}%'
         FORMAT_STR_INVOKE_SCRIPT = \
             'call:_ament_prefix_bat_call_script "{script_path}"'
-        FORMAT_STR_REMOVE_TRAILING_SEPARATOR = 'if "%{name}:~-1%==";" ' \
-            'set {name}=%{name}:~0,-1%'
+        # can't use `if` here since each line is being `call`-ed
+        FORMAT_STR_REMOVE_TRAILING_SEPARATOR = \
+            'call:_ament_prefix_bat_strip_trailing_semicolon "{name}"'
     else:
         assert False, 'Unknown primary extension: ' + args.primary_extension
 
diff --git a/ament_package/template/prefix_level/local_setup.bat.in b/ament_package/template/prefix_level/local_setup.bat.in
index 8f19bba..8f44e63 100644
--- a/ament_package/template/prefix_level/local_setup.bat.in
+++ b/ament_package/template/prefix_level/local_setup.bat.in
@@ -57,3 +57,17 @@ goto:eof
     echo not found: "%~1" 1>&2
   )
 goto:eof
+
+
+:: strip a trailing semicolon from an environment variable if applicable
+:: first argument: the environment variable name
+:_ament_prefix_bat_strip_trailing_semicolon
+  setlocal enabledelayedexpansion
+  set "name=%~1"
+  set "value=!%name%!"
+  if "%value:~-1%"==";" set "value=%value:~0,-1%"
+  :: set result variable in parent scope
+  endlocal & (
+    set "%~1=%value%"
+  )
+goto:eof