Speaker Kagodu Thimmappa made the announcement in the House.
Reddy was the lone candidate to file nomination papers for the post. He was elected to the Lower House from Gauribidanur constituency for four consecutive terms.
Chief Minister Siddaramaiah, Leader of Opposition H D Kumaraswamy (JDS), BJP leader and former Chief Minister Jagadish Shettar, KJP leader and former Chief Minister B S Yeddyurappa and BSR Congress leader B Sriramulu congratulated him on his election.