All cellular phone networks worldwide use a portion of the radio frequency spectrum designated as ultra high frequency, or "UHF", for the transmission and reception of their signals. The ultra high frequency band is also shared with television, Wi-Fi and Bluetooth transmission. The cellular frequencies are the sets of frequency ranges within the ultra high frequency band that have been allocated for cellular phone use.

Due to historical reasons, radio frequencies used for cellular networks differ in the Americas, Europe, Africa and Asia. The first commercial standard for mobile connection in the United States was AMPS, which was in the 800 MHz frequency band. In Nordic countries of Europe, the first widespread automatic mobile network was based on the NMT-450 standard, which was in the 450 MHz band. As mobile phones became more popular and affordable, mobile providers encountered a problem because they couldn't provide service to the increasing number of customers. They had to develop their existing networks and eventually introduce new standards, often based on other frequencies. Some European countries (and Japan) adopted TACS operating in 900 MHz. The GSM standard, which appeared in Europe to replace NMT-450 and other standards, initially used the 900 MHz band too. As demand grew, carriers acquired licenses in the 1800 MHz band. (Generally speaking, lower frequencies allow carriers to provide coverage over a larger area, while higher frequencies allow carriers to provide service to more customers in a smaller area.)