This paper examined long-term relationship building and customer switching behavior among mobile telecommunication operators in Nigeria. The population of this study includes all mobile telecommunication company and their subscribers in Edo State, Nigeria. The samples for this study were drawn from Mobile Network Service Providers and their subscribers. For service providers, three (3) out of the nine (9) mobile network operators were selected (Nigeria Communication Commission NCC, 2020). Morgan and Krejcie's (1970) sampling methods were implemented to choose a sample of 322 mobile telecom subscribers Godden (2004). The paper employed regression analysis to analyze and test the hypothesis formulated. The result showed that long-term relationship building (Two-way Communication, Customer retention Strategy, Customer Loyalty, and Relational Bond) had a positive statistically significant relationship with customer switching behavior among mobile telecommunication operators (Network service providers) at p>0.05. The research recommends among others that players of the mobile telecommunication Industry (mobile network service providers) should embrace the application of long-term relationship-building to achieve, sustain and retain customers' usage of their products, this will enable them to compete better with other players in the industry. Also, they should engage in relational bonding aimed at creating attachment with the customer leading to customer retention and subsequently profitability.