diff --git a/RomM/api.py b/RomM/api.py
index 8ecd2fb..b56baef 100644
--- a/RomM/api.py
+++ b/RomM/api.py
@@ -252,7 +252,14 @@ def fetch_platforms(self) -> None:
         for platform in platforms:
             if platform["rom_count"] > 0:
                 platform_slug = platform["slug"].lower()
-                if self.file_system.is_muos:
+                if (
+                    platform_maps._env_maps
+                    and platform_slug in platform_maps._env_platforms
+                    and platform_slug not in self._exclude_platforms
+                ):
+                    # A custom map from the .env was found, no need to check defaults
+                    pass
+                elif self.file_system.is_muos:
                     if (
                         platform_slug not in platform_maps.MUOS_SUPPORTED_PLATFORMS
                         or platform_slug in self._exclude_platforms
@@ -452,7 +459,12 @@ def fetch_roms(self) -> None:
         _roms = []
         for rom in roms:
             platform_slug = rom["platform_slug"].lower()
-            if self.file_system.is_muos:
+            if (
+                platform_maps._env_maps
+                and platform_slug in platform_maps._env_platforms
+            ):
+                pass
+            elif self.file_system.is_muos:
                 if platform_slug not in platform_maps.MUOS_SUPPORTED_PLATFORMS:
                     continue
             elif self.file_system.is_spruceos:
diff --git a/RomM/env.template b/RomM/env.template
index f6f6541..96d0b7b 100644
--- a/RomM/env.template
+++ b/RomM/env.template
@@ -15,3 +15,8 @@ COLLECTION_TYPE=collection
 
 # Do not display collections with these names (comma separated)
 # EXCLUDE_COLLECTIONS=""
+
+# Map RomM slugs to filesystem directories
+# For example, if your PlayStation directory is called "psx":
+# CUSTOM_MAPS='{"ps": "psx"}'
+# CUSTOM_MAPS=''
diff --git a/RomM/filesystem.py b/RomM/filesystem.py
index 46699d2..bc8828b 100644
--- a/RomM/filesystem.py
+++ b/RomM/filesystem.py
@@ -96,6 +96,9 @@ def _get_platform_storage_dir_from_mapping(self, platform: str) -> str:
                 platform, platform_dir
             )
 
+        if platform_maps._env_maps and platform in platform_maps._env_platforms:
+            platform_dir = platform_maps._env_maps.get(platform, platform_dir)
+
         return platform_dir
 
     def _get_sd1_platforms_storage_path(self, platform: str) -> str:
diff --git a/RomM/main.py b/RomM/main.py
index be8318e..0122814 100644
--- a/RomM/main.py
+++ b/RomM/main.py
@@ -2,6 +2,8 @@
 import sys
 import zipfile
 
+import platform_maps
+
 # Add dependencies to path
 base_path = os.path.dirname(os.path.abspath(__file__))
 libs_path = os.path.join(base_path, "deps")
@@ -48,6 +50,9 @@ def apply_pending_update():
     os.makedirs(os.path.dirname(log_file), exist_ok=True)
     sys.stdout = open(log_file, "w", buffering=1)
 
+    # Read any custom maps
+    platform_maps.init_env_maps()
+
 
 def cleanup(romm: RomM, exit_code: int):
     romm.ui.cleanup()
diff --git a/RomM/platform_maps.py b/RomM/platform_maps.py
index 99bf4e8..ac770d2 100644
--- a/RomM/platform_maps.py
+++ b/RomM/platform_maps.py
@@ -1,3 +1,6 @@
+import json
+import os
+
 # Manual mapping of RomM slugs to device folder names and platform icons for es systems
 # This is sometimes needed to match custom system folders with defaults, for example ES-DE uses roms/gc and some Batocera forks use roms/gamecube
 # https://gitlab.com/es-de/emulationstation-de/-/blob/master/resources/systems/unix/es_systems.xml
@@ -192,3 +195,30 @@
 SPRUCEOS_SUPPORTED_PLATFORMS_FS = frozenset(
     SPRUCEOS_SUPPORTED_PLATFORMS_FS_MAP.values()
 )
+
+_env_maps = None
+_env_platforms = None
+
+
+def _load_env_maps() -> dict[str, str]:
+    raw = os.getenv("CUSTOM_MAPS")
+    if not raw:
+        return {}
+    try:
+        loaded = json.loads(raw)
+        return loaded
+    except json.JSONDecodeError as e:
+        print(f"Error: CUSTOM_MAPS is an invalid JSON format: {e}")
+        return {}
+    except Exception as e:
+        print(f"Error: Unexpected error: {e}")
+        return {}
+
+
+def init_env_maps():
+    global _env_maps
+    global _env_platforms
+    if _env_maps is None:
+        _env_maps = _load_env_maps()
+    if _env_platforms is None:
+        _env_platforms = frozenset(_env_maps.keys())