Recent American research has explored developmental trends in gender segregation of children's peer groups. However, it is important to differentiate systematic trends in children from systematic changes in their environments. This report, based on data gathered from 1972 to 1975, presents evidence on gender segregation in Kipsigis children's peer groups in Kokwet, a rural community in Kenya. Gender segregation is examined in culturally characteristic settings and is discussed in relation to both developmental and cultural issues. Observational data from 152 children ages 18 months to 9 years reveal that there is no segregation by gender in peer groups until around the age of 6. At that time, changes in settings, parental expectations, and customary duties result in an increase in the proportion of same-sex peers in the peer group. Even within this pattern, there is some evidence that children do not interact more with same-sex peers. A contrast is drawn with the adult pattern of gender segregation, and emphasis is given to the importance of culture and development as interactive systems. (Author/RH)