National level production of livestock and livestock products in Kenya has increased over the years even though many households involved in livestock production have continued to be poor and food insecure. It is perceived that poor performance of dairy businesses is stemming from poor business growth caused by certain business related factors. Consequently, a study was conducted to establish factors influencing business growth of smallholder dairy farming enterprises in Imenti South District of Meru County, Kenya. The objectives of the study were to establish the influence of farmer’s business management skills, and extension support services on the growth of dairy farming business. The study also explored complementary relationships between dairy farmers and horticultural crops growers in the study region. The research employed descriptive survey design using questionnaires.The study had a target population of 5,993 farmers selling milk through cooperative societies or milk marketing groups in Imenti South District. Sample sizes of 190 dairy farmers were randomly selected using systematic proportionate random sampling technique. The study established that business management skills influence growth of diary enterprises and that interaction with extension service providers positively impacted on the earnings of the dairy farmers. Further it was established that the size of the dairy businesses are not directly related to age of the enterprises implying stagnation of the older enterprises as it is not consistent with growth model of business enterprises . Joint venture between dairy farming and horticultural crop growing were also found to be beneficial to farmers in the study areas because of its complementary nature through use of manures for horticulture.