A Mobile Network Operator (MNO) is a company that provides wireless communication services to mobile device users. They own and manage the infrastructure, such as cell towers and network equipment, necessary for transmitting voice and data. MNOs offer various plans that allow customers to make calls, send texts, and access the internet on their mobile devices. MNOs typically operate under their own brand and may also provide services through virtual operators, known as Mobile Virtual Network Operators (MVNOs). Examples of MNOs include Verizon, AT&T, and T-Mobile, which serve millions of customers worldwide.