The First 48 is an American documentary news magazine television series on A&E filmed in various cities in the United States, offering an insider's look at the real-life world of homicide investigators. While the series often follows the investigations to their end, it usually focuses on their first 48 hours, hence the title.

Each episode picks one or more homicides in different cities, covering each alternately, showing how detectives use forensic evidence, look outs, witness interviews, and other advanced investigative techniques to identify suspects. While most cases are solved within the first 48 hours, some go on days, weeks, months or even years after the first 48.

The series was nominated for a Distinguished Documentary Achievement Award in the Continuing Series category by the International Documentary Association. By season 6, The First 48 had become the highest-rated non-fiction justice series on television and had gained critical acclaim along with controversy. The season 8 episode "Gone", which aired on January 1, 2009, garnered a domestic audience of 2.3 million viewers, becoming the series' most-watched episode at the time. In Season 4, the series began producing and airing episodes in high definition.