Personality research has been focused on different aspects of the self, including traits, attitudes, beliefs, goals, and motivation. These aspects of the self are used to explain and predict social behaviour. The present research assessed generalized beliefs about the world, termed 'social axioms' (Leung et al., 2002), and examined their additive power over beliefs about the self in explaining a communal behaviour, that is, modesty. Three studies predicted reported modest behaviour among Mainland Chinese, Hong Kong Chinese, East Asian Canadians, and European Canadians. In addition to self-reports in Studies 1 and 2, informant reports from participants' parents and close friends were collected in Study 3 to construct a behavioural composite after examining the resulting multitrait-multimethod matrix and intraclass correlations. World views (operationalized as social axioms) explained additional variance in modest behaviour over and above self-views (operationalized as self-efficacy, self-construals, and trait modesty) in both Eastern and Western cultures. Variation in reports on three factors of modest behaviour was found across self-, parent, and friend perspectives, with significant differences across perspectives in self-effacement and other-enhancement, but not in avoidance of attention-seeking. Copyright © 2017 The British Psychological Society.