The National Indoor Football League (NIFL) was a professional indoor football league in the United States. For their first six years, the league had teams in markets not covered by either the Arena Football League or its developmental league, AF2, however, that changed briefly with their expansion into AFL markets such as Atlanta, Denver, and Los Angeles, and AF2 markets such as Fort Myers and Houston. Green Bay Packers head coach Matt LaFleur, Buffalo Bills running back Fred Jackson, New Orleans Saints quarterback John Fourcade and Pittsburgh Steelers Super Bowl running back Bam Morris, all played in the NIFL. The league folded in 2008.

The NIFL, based in Lafayette, Louisiana, was founded by Carolyn Shiver. The league started operations in 2001, with many teams coming from Indoor Football League being bought the previous year and folding operations. In 2002, the league added in the teams from the Indoor Professional Football League. 2003 was the most successful year for the league as 24 teams played a mostly complete schedule, with few cancellations.

Before the 2005 season, nine teams left the league to form United Indoor Football. That same year, the Intense Football League ceased operations and four teams from there joined the league. Those teams however, left the league before the 2006 season started.

For the 2005 season, the NIFL had an agreement with NFL to handle referee assignment and training.^[1]

The 2006 season, was the most chaotic for the league to that point. Ten expansion teams were added to the league, but nine of them had problems that reflected badly on the league. The most notable situation was the owner of the Montgomery Maulers firing the entire team.^[2] None of the ten expansion teams returned to the league for the next season.

The 2007 season started with the addition of several league-owned expansion teams, primarily to supplement games with the returning teams. However, the teams were all poorly funded and had problems fielding competitive squads. The San Diego Shockwave were declared the official league champion. The league then officially folded prior to the 2008 season.

In 2016, a new website announced that the league operations were relaunched by Carolyn Shiver with announced goal of bringing 34 teams into the former AFL markets starting in the 2017 season. As of June 2016, the league was looking for local team ownership under the league's business model.^[3]

• List of leagues of American football
• Indoor Bowl