Oswald Jacob Groenings (later Birkbeck, 20 May 1880 – 24 March 1965) was a British track and field athlete who competed in the 1908 Summer Olympics. He was born in Middlesbrough and died in London. In 1908 he was eliminated in the semi-finals of the 400 metre hurdles competition after finishing second in his heat. He also participated in the 110 metre hurdles event and was eliminated in the semi-finals again after finishing fourth in his heat.