"My constituents can have confidence that Ken Paxton will be an effective attorney general who will relentlessly fight the liberal agenda of President Obama," Estes said in a statement.
Estes previously supported Texas Railroad Commission Chairman Barry Smitherman's primary bid for the position, but Smitherman did not make it to the runoff. Paxton is currently facing state Rep. Dan Branch, R-Dallas, who earned more than 33 percent of the vote in March. Paxton earned more than 44 percent.
Since emerging from the March 4 election with the lead, Paxton has announced a number of endorsements. The highest profile of the bunch so far was last week's endorsement from cable news host and former Arkansas Gov. Mike Huckabee and his political action committee, Huck PAC.