Thought I'd post this PSA for the record as it had me stumped for a long while. I needed to use steam leaderboards in my steam game but I was unable to get steam_stats_ready() to return true, this is the first thing you need to do and is part of the api initilisation process https://docs.yoyogames.com/source/dadiospice/002_reference/steam api/steam_initialised.html if you cannot get steam_stats_ready() to return true you cannot go on to read\write leaderboard data. I had created a leaderboard in Steamworks for my game but when I used my games APP_ID in GMS2 steam_stats_ready() would always return false, if I used the steam demo game (space wars) APP_ID 480 it returned true and I could access those leaderboards. The fix is to create atleast one "Stat" for your game in "Steamworks > App Admin > Stats & Achievements" even if you dont plan to use any, once I did this steam_stats_ready() returned true and I was able to read\write to my leaderboard. Not sure if this is a steam thing or an issue with GMS2 but the fix is easy.