Immigration has risen substantially in many European economies, with far‐reaching if still uncertain implications for labour markets and industrial relations. This article investigates such implications, focusing on employment flexibility, involving both ‘external flexibility’ (fixed‐term or temporary agency and/or involuntary part‐time work) and ‘internal flexibility’ (overtime and/or balancing‐time accounts). The article identifies reasons why immigration should generally increase the incidence of such flexibility, and why external flexibility should rise more than internal flexibility. The article supports these claims using a dataset of establishments in 16 European countries.