Exploring the relative influence of nature and nurture on human motor development is one of the important topics in kinesiology and physical education. Although socio-cultural environmental characteristics affect children’s physical activity patterns, questions remain as to why children in different cultures choose different types of physical activities. To facilitate understanding of these questions, assessing psychological factors such as motivation for participation may be critical. Thus, the purpose of this research was to examine cultural influences on motivation for participation in physical activities among three ethnically diverse groups of children. A total of 424 children from 12 to 16 years of age participated in this research (202 females and 222 males: Chinese-PRC, 73 females and 82 males, American born Chinese-ABC, 66 females and 56 males, and American-USA, 63 females and 84 males). A physical activity motivation questionnaire (Gill, Gross, & Huddleston, 1983) was used. ABC and USA children were given the English version of the questionnaire while PRC children were given the Chinese version of the questionnaire. To ensure equivalence of both versions, a back-translation was implemented. Pilot work was also conducted with both versions to assure the correct interpretation of the questions. Based on the nature of the question, the 30 questions of the questionnaire were categorized into three areas: (1) motivations related to skill improvement or competition; (2) motivations related to social activities or fitness enhancement; and (3) other motivations (travels, having fun, using equipment, etc.). The percentage of each type of motivation was examined by Chi-Square analyses. The results indicated that the USA participants, regardless of their gender, appear to take part in sport or physical activity primarily for skill improvement and competition. On the other hand, both male and female PRC participants tended to favor socializing and getting fit more as motives for participation than their USA and ABC counterparts. In addition, the ABC participants seemed to enjoy physical activities and sports for relatively broad reasons. Overall, the findings suggest that children in different cultures may be subject to environmental influences, as a result, showing differences in motivation for participation in physical activities or sports. Examining ethnicity or biological influence on children’s physical, psychological, and motor development is needed to further our understanding of child development. Understanding cultural differences in children’s motives for participation may result in a better organization of physical activity opportunities for child sport experiences and motor skill development in a multi-cultural society.