As social networking sites (SNS) have been actively used as a platform for the political participation, this study investigates factors influencing SNS users’ political participation intention and behavior in developing countries. More specifically, based on the integrated model of Unified Theory of Acceptance and Use of Technology (UTAUT) and Civic Voluntarism Model (CVM), we develop a research model on how technological factors (e.g., performance expectancy, effort expectancy, social influence, and facilitating conditions) as well as social factors (e.g., political interests and experience) influence Facebook users’ political participation intention, which lead to actual political participation behavior, focusing on the Cambodian context. Our research model will be empirically tested with survey samples gathered from Cambodian Facebook users and their actual political behaviors, measured by counting actual comments of each survey respondent one month after the survey. While prior studies have only focused on either technological or social influencing factors on online political participation, this paper is among the first attempts to investigate them from integrative and comparative perspectives. By highlighting the relative impacts of each factor in the context of developing countries, where direct and public challenging or criticizing on the government is still a fear for most citizens, this paper would provide an important lesson for other developing countries with a similar political environment.