Research on risk behaviors among men who have sex with men (MSM) is often based on individualistic models of health behavior, but sexual behavior is inherently social in nature and often determined by constituents of social networks. The objective of this study was to examine relationships among social networks, network norms of condom use, and safer sex. A respondent-driven sampling study recruited 350 MSM in the Shenzhen region of China between November and December 2007 and collected information on network components (relations, structures, and functions) and HIV risk behavior among egos (those interviewed) and their network alters. A total of 2385 alters were nominated by the 350 egos. Egos reported an average of 4 nonsexual relation alters and 2 sexual-partner alters. Egos perceived receiving more tangible and emotional support from nonsexual relation alters than from sexual-partner alters. Two thirds (69%) of egos consistently used condoms. Sixty-seven percent of egos reported having 1 or more alters who always encouraged egos to use condoms, 84% had 1 or more alters who consistently used condoms, and 55% had 1 or more alters who insisted on condom use. Both subjective and descriptive norms were positively associated with consistent condom use. Network components were associated with the levels of the two norms. These findings suggest that social network components may activate or strengthen condom use norms within networks, which, in turn, determine consistent condom use among MSM. HIV behavioral interventions need to target the promotion of safer sex practices through enhancing peer norms of condom use within networks.