This study investigated the associations between parent-child connectedness and sexual behaviors among adolescents living in informal settlements in Nairobi, Kenya, a vulnerable group with respect to reproductive health outcomes. The study was based on data from the Transition to Adulthood project, a study designed to follow adolescents aged 12-22 for 3 years in the informal settlements of Korogocho and Viwandani. Direct face-to-face questions were asked to adolescents about parenting variables and sexual behaviors. This study used a subsample of 689 sexually experienced 12-22-years-olds at Wave 2. Bivariate analysis compared gender differences for three outcomes-sexual activity in the 12 months prior to the survey and, among those who had had sex in this period, multiple sexual partners and condom use at last sex. Multivariate logistic regressions were used to identify associations between these outcomes and the quality of parent-child connectedness. About 60% of adolescent females and males were sexually active in the 12 months prior to the survey. The multivariate results showed a strong association between the quality of parent-child connectedness and condom use among adolescent males. Living with related or unrelated guardians (versus living with biological parents) was also associated with higher odds of multiple sexual partners and lower odds of condom use at last sex among adolescent females and with higher odds of sexual activity among adolescent males. Sexual and reproductive health programs targeting adolescents living in Nairobi informal settlements would benefit from attention to assisting parents to improve their ability to play the connectedness role.