This study examined the competitive environment’s moderating effect on the relationship between marketing mix strategies and tour firms’ performance in Kenya. The researcher adopted a descriptive research design and used a survey approach to collect pertinent data for analysis. The study population comprised all tour firms, both locally and foreign-registered, operating under the Kenya Association of Tour Operators (KATO) as of September 2019. Two hundred thirty-four tour firms were surveyed out of a population of 260 registered firms. Descriptive statistical and inferential analyses were conducted and regression analysis results were used to test the hypothesis. The study established a positive and significant moderating effect of Competitive Environment (CE) on the relationship between Marketing Mix Strategies (MMS) and the Organizational Performance (OP) of tour firms in Kenya. The study’s findings are significant to policymakers and stakeholders operating in the tourism industry.They accentuate the significance to tour firms in implementing the right kind of marketing mix strategies to maximize their organizational performance. The study recommends future studies in the same area be expanded to include other travel trade areas such as hoteliers and travel agencies. Such a study would increase the empirical knowledge in the subject matter while also extending the generalizability of the results.