McCaul is married to Linda Mays McCaul, the daughter of Clear Channel Communications founder and former chairman Lowry Mays and sister of its former CEO Mark Mays. In 2011, "Roll Call" named McCaul as one of the wealthiest members of the United States Congress, surpassing then U.S. Senator John Kerry (D-MA). His net worth was estimated at $294 million, about 300% higher than it was in the previous year ($74 million). In 2004, the same publication estimated his net worth at $12 million: His wealth increase was due to large monetary transfers from his wife's family.