Participation of local communities in forest management decision-making has been promoted as a mechanism of improving livelihoods and forest conditions, yet the level of participation in many programs remains low. Using data from a cross-sectional survey of 924 forest-dependent households in Western Kenya, we examine the factors that support or constrain forest dependent people's participation in a Participatory Forest Management (PFM) program. We run a probit model to assess households' choice to join PFM and then compute a Participation Index (PI) for forest users' participation across different stages of the PFM program – planning, implementation and Monitoring and Evaluation (M&E). The determinants of participation are then analyzed using the fractional regression approach. Results show that over half (52%) of the respondents participated in PFM. While vulnerability to shocks, being in a farmers' group, a household's access to the forest within the previous 12 months and access to extension were associated with the likelihood of participating in PFM, the influence of the household head's age and education, access to credit and food insecurity had a negative influence. Our results reveal PIs of 41%, 49%, and 42% at the planning, implementation, and M&E stages respectively, indicating a moderate participation level. The fractional regression model shows that transaction costs associated with access to markets, gender (being male), household expenditure and expected forest benefits positively influence household participation in PFM, while the opportunity costs associated with off-farm income, distance to the forest and lack of extension have a negative influence on participation. These results point to the need to take the household context (gender, education, household expenditure and vulnerability) into consideration during planning and implementation of the forestry programs. The implication is that forest authorities should identify and implement mechanisms to enhance benefits from forests but also reduce costs of participation, especially for women.