Matthew Pennington will spend another month on loan at League One side Coventry City.
The Academy graduate will now stay at the Ricoh Arena until 7 February.
The 20-year old has been an ever present since arriving in November, making six appearances for the Sky Blues.
Pennington, whose initial loan spell was due to end on 4 January, has been playing at right-back and Sky Blues manager Steven Pressley is pleased to have extended the deal for the young Blues defender, adding he has been impressed with his professionalism since his arrival.
"We've been really impressed by Matty's performances since he has joined up with us," said Pressley.
"He has been excellent not only on the pitch, but the way he conducts himself off it is a credit to the grounding he has received from Everton.
"We're delighted to extend his spell here as he has reached all of our expectations both on and off the pitch. His attitude has been superb. He provides us with versatility in defence and we look forward to continue working with him."