William B. Callaway, FASLA (May 26, 1943 – November 25, 2014) was an American landscape architect with SWA Group, recognized for his ability to design landscapes that are timeless. Peter Walker, designer of the World Trade Center Memorial and a long-time colleague, described Callaway as being "among the icons of post-World War II practice", developing his modern style by consistently staying true to the natural character of the landscape.