Saia is an American trucking company, or a less than truckload (LTL) trucking company, that originated in Houma, Louisiana in 1924. With original operation occurring in Louisiana and Texas for the first fifty years, expansion came after 1980 when coverage began reaching into more states within the South. Further expansion happened through merges with other companies, which allowed Saia to provide service for thirty six states. Saia ranks within the top ten of LTL carriers in the United States, yielding $1.3 billion in 2014.

Saia began in 1924 in Houma, Louisiana by Louis Saia, Sr. Louis was a produce dealer who realized that there was more success in delivering produce rather than selling it. The first Saia truck was his car with the rear seats removed.

By 1970 Saia expanded and established terminals in Texas and Louisiana. Saia became one of the largest regional LTL carriers in the United States with 23 terminals throughout the Southeastern United States and revenue exceeding $50 million.

The Saia family sold Saia to Preston Trucking in 1987. The Yellow Corporation purchased Preston Trucking, along with Saia, in 1993. In 1995 Saia merged with Smalley Transportation resulting in the establishment of terminals in North Carolina, South Carolina and western Texas. In 2002 Saia and Jevic Transportation, another Yellow Corporation subsidiary, spun off to form an independent publicly traded company called SCST.

Clark Brothers Transport, Inc. was acquired in 2004 incorporating its nine state, sixteen terminal operations into Saia. In 2006 SCST sold Jevic Transportation and folded all corporate functions into Saia. Saia also began trading on the NASDAQ with the symbol SAIA. Saia expanded further with the acquisitions of The Connection Company in 2007, Madison Freight Systems, Inc. in 2007 and The Robart Companies in 2012.

Saia has 148 terminals in 34 states in the United States and Canada. Through Saia's network of partners it serves most of the United States including Alaska, Hawaii, Mexico and Puerto Rico. The three operating service groups of Saia are Saia LTL, Saia Logistics Service and LinkEx. Saia has over 9,000 employees and 26,000 shipments per day as of 2014.