The Wisconsin Republican is author of a plan to gradually transform Medicare into a voucher system in which future seniors would get a fixed amount to buy medical insurance.
Party Chairman Steve Munisteri said in statement Thursday that Ryan's "leadership on shrinking the size of government and cutting federal spending aligns well with the platform of the Republican Party of Texas."
Ryan is set to speak on the final day of the convention, which will be held in Fort Worth June 7-9.
Former presidential candidate and Pennsylvania Sen. Rick Santorum is also scheduled to be a featured speaker.
