R package DFIT. A set of functions to perform Raju, van der Linden and Fleer’s (1995) Differential Functioning of Items and Tests (DFIT) analyses. It includes functions to use the Monte Carlo Item Parameter Replication approach (Oshima, Raju, & Nanda, 2006) for obtaining the associated statistical significance tests cut-off points. They may also be used for a priori and post-hoc power calculations.