graphicsView is the PyQtGraph plot object as promoted in my Qt Creator .ui project. I can access it just fine out of the thread. It seems that even if I'm using another thread to manage my data I need to somehow do the actual graphics updating in the main "Qt UI" thread ... not sure how to do this as most examples use timers instead of threads. Ultimately my data will be getting pushed in so timers aren't really what I want.