This article aims to evaluate the driving forces of outsourcing strategies on the organizational performance of mobile network operators in mainland Tanzania. The objectives are to identify the driving forces of outsourcing and determine the challenges of outsourcing in telecommunication companies. The article adopted a descriptive cross-sectional survey. The selection of mobile companies is based on high market share and operation period. Findings show that customer needs for high-quality services, high-rated change in service, reduction of operational expenditure, and accessing the world’s capability are among the major driving forces for outsourcing. Dependability, loss of security, hidden costs, and selection of competent partners to mention a few are the challenges faced by telecom companies. It is noted that outsourcing enables network operators to advance their organizational performance in terms of operating cost, productivity, profitability, and market share. However, customer satisfaction suffers due to the inconsistency of the quality of service offered. Therefore, it is advised that mobile operators closely monitor outsourcing service providers to ensure that agreed service levels are met, thereby, safeguarding the reputation of the company to customers.