The General Evaluation Scale (GES) has been widely employed to assess attitudes toward outgroups, including ethnic and religious prejudice. However, validation within the Indonesian context has not been conducted. Using two studies (Study 1, religious prejudice; Study 2, ethnic prejudice), we provide evidence of psychometric properties of a six-item GES for measuring ethnic and religious prejudice based on factor structure, composite reliability, and convergent validity in Indonesia. The results demonstrate an acceptable model fit for a single-factor structure characterized by high internal consistency (McDonald’s Omega/ω = 0.93 in Study 1, ω = 0.94 in Study 2). Furthermore, the scale exhibits solid convergent validity, as evidenced by its correlations with the blatant and subtle prejudice scale (r = −0.44 in Study 1, r = −0.74 in Study 2) and the feeling thermometer scale (r = 0.60 in Study 1, r = 0.78 in Study 2). In summary, this research unequivocally establishes the GES as a valuable instrument for measuring religious and ethnic prejudice in the Indonesian context, underpinned by its robust psychometric properties. Nevertheless, it underscores the need for further investigations with diverse samples and varying social contexts to bolster the scale’s reliability and applicability.