KBJ Architects, Inc. (KBJ) is an American architectural firm based in Jacksonville, Florida. The firm designed 17 of the city's 30 tallest buildings and "created Jacksonville's modern skyline", according to The Florida Times-Union newspaper. The firm designed the first high-rise in downtown Jacksonville, the 22-story Aetna Building, which opened in 1955. It took pride in "having the second-largest number of architects of any Florida firm", according to a 1997 article in The Florida Times-Union.