The Houston Marathon is an annual marathon held every January in Houston, Texas. With thousands of runners and spectators, it is the largest single day sporting event in the city. It is run concurrently with a half marathon and a 5 km race. The 2007 race included the first-ever satellite running of the event, run simultaneously in Fallujah, Iraq.

The first marathon, run on December 30, 1972, featured 113 runners and a crowd of approximately 200 people. The 2014 edition included a 5K event run Saturday, January 18th and the marathon and half marathon run on Sunday, January 19th. The 5K event had close to 5,000 runners while the marathon and half marathon had nearly 13,000 runners each. The races bring crowds of nearly one half million to view the runners. The 1979 edition of the competition hosted the national marathon championship race for men and women. Houston was selected for the women's Olympic Trials in 1992 and held the USATF women's marathon championship in 1998. The half marathon course hosted the USATF Men's Half Marathon Championship from 2005 to 2008, and also hosted the women's event in 2007 and 2008. The 2012 U.S Olympic Marathon Trials for both men and women were held the Saturday prior to the Sunday races.