Jason, Kylie Kelce Attend Funeral Of Dad Ed's Partner

Jason Kelce was by his dad's side as Ed Kelce said his final goodbyes to his girlfriend on Thursday ... attending Maureen Maguire's memorial service with Kylie Kelce.

Travis Kelce's big brother and sister-in-law made the trip to Gladwyne, Penn. to celebrate the life of Maguire ... who died "peacefully" nearly one week ago.

Jason wore a button-down shirt and tie ... while Kylie opted for a black dress. Ed donned a full suit -- and was seen helping carry Maguire's casket throughout the funeral.

It's unclear where Ed and Maureen met and how long they'd been dating, but according to an obituary he posted on his Facebook page, the elder Kelce was "beloved" by Maureen.

In the obit, Ed's GF was described as a "devoted mother" with "impeccable taste" ... who loved life with an unmatched passion and joy.

Maureen actually crossed paths with Taylor Swift in the final years of her life ... with Ed telling the L.A. Times in February she would crack jokes with the popstar about some of her interactions with Ed.

Swift didn't make it to funeral, and neither did Travis ... as the Kansas City tight end is still getting ready for the Chiefs' season at training camp in Missouri.

Maureen -- who leaves behind three children, six grandchildren, and two siblings -- was 74 years old.