Sustainability of a project is a great challenge in most developing countries including Kenya. Evidently, it is sustainability that differentiates between women group projects that have succeeded and ones that have failed. Women group projects need resources to enable them continue to provide the services to members and also the community at large. Women groups have for long time relied on the donor funding in order to support their project activities through donations and grants. However, this funding is at times not enough to cater for the project operations and project implementation and later the sustainability of these projects. Most of the projects initiated by women groups in Vihiga County have become unsustainable especially when the donors exit. This study sought to bring out the influence of resource mobilization on sustainability of women group projects in Vihiga County, Kenya. The target population was 491 women group projects in Vihiga County. The respondents of this study comprised women group's officials and project committee members of women group development projects in Vihiga County. Stratified random sampling of projects and projects committee members was done to obtain a sample size of 97 projects. Questionnaires were used in data collection processes. The data collected was analyzed using both descriptive and inferential statistics. The variables namely acquisition of financial resources, mapping human resources, acquisition of physical resources and community participation were regressed and the study findings showed that all independent variable significantly and positively influenced the sustainability of women group projects in Vihiga County, Kenya. The study recommends that Women groups should be trained on resource mobilization tips including the diverse methods for acquiring financial resources starting with preparing for fundraising, assessing and using organizations strengths and soliciting external funding source. Human resource mapping should be conducted in women groups to reduce expenditure on external sources. Women groups should have necessary tools, office equipment and machinery to run their projects. Finally, the community should be involved by the women groups in the implementation of women group projects at all phases.