With its heavy traffic and technological capabilities, social networking sites (SNSs) introduced a new means of building and maintaining social relationships. This study aims to identify underlying factors and causal relationships that affect behavioral intention to use SNSs. For this purpose, this research developed an extended technology acceptance model (TAM), incorporating subjective norm (SN) and perceived social capital (PSC). Exploratory correlation and path analyses were conducted to examine the relationships between five constructs; perceived usefulness (PU), perceived ease of use (PEOU), subjective norm (SN), perceived social capital (PSC), and intention to use (IU). The results showed that PU and PEOU had robust effects on the user's intention to use SNSs. The research findings also demonstrated that SN and PSC were significant predictors of both PU and PEOU, and therefore should be considered as potential variables for extending TAM.