The Nigeria international, 20, has made 11 Championship starts since joining Boro on loan in January.
Omeruo will go back to Stamford Bridge next month, but Karanka admits that he would welcome the opportunity to re-sign him on a season-long deal after the summer.
Karanka told the Gazette: "It could be possible, He's a good lad, a very good player, he is improving, he is going to go to the World Cup so I am very happy with him.
"He always gives 120% on the training pitch. Even when he wasn't playing he had a good attitude."
Omeruo has yet to feature for Chelsea's senior team. He spent last season on loan at ADO Den Haag in Holland.