The Motivation for Ethno-cultural Continuity (MEC) scale was developed to capture the agency of minority individuals in the long-term acculturation of their group and their dedication to cultural persistence over many generations. Study 1 presents the construction and validation of a pilot MEC scale, an 18-item unifactorial measure demonstrating good reliability (α = 0.95), convergent validity via its significant correlations with Collective Self-Esteem (r = 0.67), Perceived Collective Continuity (r = 0.54), Perceived Group Entitativity (r = 0.32), and discriminant validity in that it was unrelated to attitudes toward Assimilation (r = -.10, ns). Study 2 confirmed the structural equivalence of the final 10-item MEC scale and examined its prevalence and function across samples of New Zealand Jews, Maori, and Chinese (n = 311). Good scale reliability was found across cultures (α = 0.94 to 0.95). As expected, higher values were found among Jews and Maori than Chinese. Together with traditional ethnocentric predictors, MEC predicted intentions for endogamy and in turn selective dating for Jews and Maori, but not for Chinese. Results are interpreted in terms of existential uncertainty experienced by "small peoples" and the impact of collective interests on individual behavior.