Frost Bank is a Texas-chartered bank founded in 1868 and based in San Antonio, with 139 branches across the state. Frost is one of the largest Texas-based banks.The company offers a full range of commercial and consumer banking products, investment and brokerage services and insurance products to customers throughout Texas.

Frost is a subsidiary of Cullen/Frost Bankers, Inc., a financial holding company, also based in San Antonio.

In June 2012, Frost converted its 113-year-old federal charter into a state charter.

The bank was founded in 1868 in San Antonio by Col. Thomas Claiborne (T.C.) Frost. Since then it has acquired many other Texas banks. In 1977, Frost Bank Corp. and Cullen Bankers, Inc. of Houston merged, forming the holding company, Cullen/Frost Bankers, Inc.

In 1982 Cullen/Frost Bankers and United States National Bancshares, Inc. (USNB) of Galveston, Texas merged, but Frost operated USNB separately for nearly two decades. As new financial services legislation allowed banks to broaden the services they offered customers, Cullen/Frost folded the USNB charter into Frost's in 2000. With this action, the last bank using the federally forbidden United States National Bank title ceased to exist.

Growing through the years, Frost was the 10th largest bank headquartered in Texas in the early 1980s. A decade later, it would be the biggest. As energy prices plunged, real estate slumped and the banking industry collapsed, Frost emerged as the only one of the top-10 banks based in Texas to survive intact, without federal assistance or a merger with an out-of-state financial institution.

Frost was the first bank in the nation to decline TARP bailout funds during the financial crisis of 2008 and has more than doubled in asset size since year-end 2007 by growing its banking, investments and insurance business. On December 31, 2014, Frost Bank had $28.6 billion in assets, $35.6 billion in combined trust, brokerage and advisory assets, and 126 locations in the San Antonio, Austin, Corpus Christi, Dallas, Fort Worth, Houston, Rio Grande Valley and Permian Basin regions.

This growth has solidified the company’s Texas base and fueled an expansion of services. Today, Frost offers a broad range of financial services, including business and consumer banking; investment, trust, retirement and financial management services; insurance and investment banking.

Cullen/Frost Bankers, Inc. was originally listed on NASDAQ in 1977, but began trading under the symbol "CFR" on the New York Stock Exchange in 1997.

Frost Bank branch in San Antonio on the city's Northwest Side.

The Frost Bank Tower is one of the tallest buildings in Austin, Texas.

See also: List of museums in Central Texas