A social identity refers to (1) whether people consider a group to be an ingroup along with (2) the psychological meaning of that ingroup (Tajfel, 1978). Social identification and disidentification are two constructs that describe different natures of the psychological meaning of an ingroup. Besides self-reported measures, the Identity Implicit Association Test (identity IAT), and the Match-Mismatch Paradigm (MMP) are the most frequently used measures to assess social identity. In three studies (N = 87, N = 96, N = 137) we tested whether the MMP and identity IAT distinguish between social identification, non-identification, disidentification, and non-categorization. The findings indicate that the identity IAT mostly assesses self-categorization whereas the MMP is sensitive to the specific psychological meaning of an ingroup.