Lake Naivasha fishery has been one of the most known sources of protein for most fringe communities in and around Naivasha. About 4000 livelihoods depend on the lake’s fishery resource, both directly and indirectly, thus pose concerns on the future sustainability. The ultimate aim of this study was to explore efforts, costs and optimum levels of fishery exploitation in Lake Naivasha. The study relied on fish landings and fishing effort statistics recorded between 1980 and 2017 by Fisheries Department. Data was analyzed using Gordon Schaefer’s model and excel operating software. A regression model was run to develop graphs that explained the relationship between total costs, total revenues, harvests and number of boats. Consequent to the main aim, the study sought to determine the total costs of fishing along with revenues generated. Findings show an increase in number of operational boats from twenty-six (26) in 1980 to fifty boats (50) in 2013. Thereafter, fishing boats increased significantly to one hundred and seventy-six (176) by 2017. Such a significant and unprecedented increase in efforts adversely affected natural fish stock and brooders of the major fish species in the fishery. Information in this paper will inform decisions on resource economics and management of fishing activities in Lake Naivasha, Kenya.