The 27-year-old was one of nine men arrested in October 2010 on suspicion of conspiracy to defraud following a joint operation by Merseyside Police and the Gambling Commission.
The probe followed reports from some bookmakers of irregular betting patterns on Motherwell's 2-1 defeat by Hearts last December, during which Jennings was sent off. He denied the allegations.
The midfielder's solicitor Nick Melville told BBC Scotland: "We've received information from Merseyside Police that in relation to Mr Jennings there'll be no further action.
"Mr Jennings stated from the outset that he's had no involvement whatsoever with any criminal activity and this vindicates his stance throughout."