A: The 11-inch Deluxe Metal Tray does will not affix or attach to a ladder tray. However, many painter's sit their roller trays on their ladder tray. The dimensions of the Wooster Deluxe Metal Tray are 16-1/2" L x 11" W x 2-1/2" D. We are unsure the dimensions of your ladder tray, but we also offer many different bucket and tray options. If you are struggling to find the perfect option for your projects, please contact Wooster Customer Service at 800-392-7246. We would be happy to help you find the perfect solution.