Industrial relations studies have struggled to explain the variations in human resource (HR) practices in firms operating in the same institutional contexts and sectors and facing similar market pressures. Budd, Pohler, and Huang's (2021) model on the frames of reference used by managers and employees constitutes a notable exception, as it focuses on how actors view HR practices. We build on this model and critique and extend it by including unions as actors and exploring employers' and unions' frames concerning HR practices and the ensuing outcomes. We also develop an analytical framework composed of workplace‐level relational and beyond‐workplace external elements. We invite future research to show the empirical validity of our model and framework.