Advertisement remains a major tool for telecom companies to gain market share in Nigeria. The study investigated the effects of advertisements on consumer brand preference among the major telecom brands (MTN, Airtel, and Glo) in Nigeria. A mixed-methods approach was used, collecting data through questionnaires and interviews with 200 university students and 80 people at a market. The study found that advertisement creates awareness and influences consumers' choices, with 60% of MTN users reporting they chose the brand after learning about promos from advertisements. However, perceived quality may outweigh advertising, as MTN maintains the largest market share despite competitors' advertisements, since it is seen as providing the best reception. Celebrity endorsements can increase brand recall