The study analyzed the gender disparity in agricultural extension service delivery between female- headed and male-headed households in Gedeb Woreda of West Arsi zone. The specific objectives were to assess the types of agricultural extension services provided to farmers; to identify the level of farmers’ participation in agricultural extension services delivery; and to assess the gender disparity and its determinants in agricultural extension service delivery. Purposeful sampling method was employed to select Peasant Kebele Administrations of a maximum number of female- headed households at an aim to get the required number of FHHs for the study. Based on this, cross-sectional data were collected from 160 respondents that systematically selected for this study whereby 51 were female-headed and 109 were male-headed households (MHHs). The result of this study revealed that the educational level of the household heads, livestock holding, access to credit; access to extension contact; farm size and mass media exposure had a significant and positive influence on the participation of households in full extension package service.