Geosocial networking applications (GSN apps) have become increasingly popular among gay, bisexual and other men who have sex with men (MSM). Our study sought to understand whether inclusion of individuals met via GSN apps in participants' social networks was associated with increased HIV risk behaviors among a probability sample of GSN app using MSM (N = 295) recruited in Los Angeles, California. Approximately 20 % of participants included a GSN app-met individual as one of their top five closest social network members. Those with a GSN app-met network member had more recent (past 30-day) sexual partners (B = 1.21, p < 0.05), were nearly twice as likely to have engaged in unprotected anal intercourse (UAI) with their last sexual partner (AOR = 2.02, p < 0.05), and were nearly four times as likely to have engaged in UAI with their last GSN app-met sexual partner (AOR = 3.98, p < 0.001). Network-based interventions delivered via GSN apps may be useful in preventing the spread of HIV among MSM.