Chapter 3 introduces an original, multi-item measure of group empathy: the Group Empathy Index (GEI). The GEI modifies the Interpersonal Reactivity Index (IRI), which mainly captures empathy toward close family and friends. The GEI taps empathy for strangers, primarily members of socially distinct groups. The two measures are similar on their face, but they are conceptually and functionally distinct. The chapter also explores the measurement properties of a long and short version of the GEI, employing data from multiple surveys. Both versions of the GEI are reliable and valid indicators of the underlying construct. We also find that the GEI is not reducible to personality dimensions such as authoritarianism or other group-oriented predispositions such as social dominance orientation (SDO), racial resentment, ethnocentrism, linked fate, ideology, and partisanship.