The Swans were reportedly lining up a January move for the Dutch Under-21 international after he impressed during a month-long loan stay at the Liberty Stadium, scoring twice in four league matches including the winner in the South Wales derby.
However, 22-year-old Emnes has been a regular in the Boro side since he was recalled last month and after he won the vital penalty which set up the 1-0 win over Cardiff on Saturday, Mowbray wants to keep hold of him.
He told the club's official website: "I don't think there's any chance of that (Emnes going back to Swansea).
"There are financial implications at this football club but I don't think Marvin is a major problem for us.
"When Marvin wasn't in the team, the team didn't have an outlet, someone they could hit a ball over the top to who would find space, but he gives us that. He's showed me on Saturday he can play up front and in a wide position."
Source: PA
Source: PA