8 pages., via online journal., Social media provides huge opportunities and incentives that could ease promotion of agricultural extension, facilitate real-time service delivery and enable wider farmer coverage. Ineffective dissemination approaches, expanding farmer population, low staffing, and aging agricultural extension agents continue to negatively affect the provision of agricultural extension services in Kenya. Despite the social media potential in agricultural communication, lack of awareness and low usage in the rural areas of developing countries have been documented. This study sought to establish the level of social media familiarity among smallholder rural farmers with the aim of exploring the possibility of usage in agricultural extension. The study was undertaken in Thika Sub-County of Kiambu County on 140 farmers through a researcher administered semi-structured questionnaire. Probability-proportional-to-size sampling method was employed to derive the sample size from existing extension farmer groups. Simple random sampling technique was further used to identify the actual respondents from each group. A low level of social media familiarity was established among the farmers with education, age and gender having significant influence. The study recommends awareness creation initiatives to promote social media familiarity with a particular focus on women who form the bulk of the farmers but with the lowest level of social media knowledge.