Concept-based teaching is presumably more effective than popular procedure-based instruction in helping students develop conceptual understanding, an important conceptual base for mathematics teaching reforms in many countries. This study examined the extent to which this assumption is true by controlling the influences of student socioeconomic status and mathematics self-concept. It analysed TIMSS 2015 data related to eighth-grade students' algebra and geometry performances and relevant teacher survey in Hong Kong, Chinese Taipei, and the US and revealed the following. Neither concept- nor procedure-based teaching approaches significantly contributed to student algebra and geometry performances in Hong Kong and the US. However, concept-based teaching significantly contributed to student performances in Chinese Taipei. Student socioeconomic status and mathematics self-concept influenced student performances in three places.