A system and method for supporting a scalable thread pool in a multi-threaded processing environments such as a distributed data grid. A work distribution system utilizes a collection of association piles to hold elements communicated between a service thread and multiple worker threads. Worker threads associated with the association piles poll elements in parallel. Polled elements are not released until returned from the worker thread. First in first out ordering of operations is maintained with respect to related elements by ensuring related elements are held in the same association pile and preventing polling of related elements until any previously polled and related elements have been released. By partitioning the elements across multiple association piles while ensuring proper ordering of operations with respect to related elements the scalable thread pool enables the use of large thread pools with reduced contention compared to a conventional single producer multiple consumer queue.