We examined the relationships between loneliness, interpersonal motives for Internet use, online communication, and friendships on Social Networking Sites (SNS) in emerging adults. Participants were 1st-year university students (N=149; Mage=20.33years; SD=2.51). Social and romantic (emotional) loneliness were indirectly related to the total number of friends reported on SNSs via social compensation and social networking motives and mechanisms of spending more time in online communication and engaging in more self-disclosure. Romantic loneliness was indirectly related to the number of new friends made on SNSs via social networking motives and online communication. These different relationships show that to understand the mechanisms by which emerging adults make friends online, it is important to consider individual differences in the type of loneliness as well as their motives for going online and their communication while online. •The social compensation hypothesis argues the Internet attracts lonely people.•The mechanism by which lonely emerging adults make online friendships is unclear.•Social loneliness was related to social compensation motives.•Romantic loneliness was related to social compensation and networking motives.•Motives predicted friendships via online communication and self-disclosure.