Abstract: A platform accessary for a ladder, including connectors for readily and securely mounting on two adjacent rungs of the ladder, by engaging the upper rung from above and engaging the next lower rung from below, with adjustment means for tightening the connectors thereon. The platform is adaptable to all rung shapes and sizes, and all types of "lean-to" ladder or extension ladders, and for mounting against either an outside corner or an inside corner of two adjacent walls. Additionally, the platform is foldable into a compact, substantially flat unit for storage and for carrying.