Social cohesion, defined as a glue holding society together, has been found to influence several aspects of human behavior. Social cohesion, being composed of social trust and social participation, is a social factor that may influence sexual behaviors. Unfortunately, studies investigating the influence of social cohesion on sexual behaviors among young people are scarce. This study examined the influence of social cohesion on safe sexual behavior among adolescents in rural Tanzania. A cross-sectional study was conducted among 403 school adolescents of the Newala district, between May and August 2010. Socio-demographic characteristics, social cohesion (social trust and social participation) and sexual behavior (age at sexual debut, intention to use and reported condom use, number of sexual partners) were obtained through self-administered questionnaires. Data analysis was performed using descriptive statistics and binary logistic regression. Sexual debut at under 13 years of age was reported by 12% of the respondent. A majority (71%) reported multiple sexual partnerships and half of the participants reported to have used a condom at their last sexual encounter. The intention to use a condom was reported by 77% of the respondents. Having multiple sexual partnerships was associated with social trust only (odds ratio: 3.5, 95% CI 1.01-12.3) whereas reported condom use was related with social cohesion (odds ratio 4.8 95% CI 1.66-14.06). Social cohesion, trust or participation was not associated with young age at sexual debut or intention to use a condom. Being a female (odds ratio 2.07 95% CI 1.04-4.12.) was associated with intention to use a condom. This study indicates that social cohesion and socio-demographic factors influence actual behavior performance and behavioral intentions. The findings point to the importance of collecting more evidence on social cohesion and sexual behaviors in different settings and designing interventions that enhance social cohesion among adolescents in order to reinforce positive sexual behaviors.