Humphreys, a former Wales international hooker and captain, joined the coaching team under Wayne Pivac in 2019 and will continue to coach the forwards under Gatland.
Jenkins, who remains Wales’ record points scorer, was first appointed as a skills and kicking coach under Steve Hansen in 2004 and worked with Gatland throughout his first tenure from 2007 to 2019.
“We are delighted that both Jonathan and Neil will stay on and be a part of Warren’s new team,” WRU CEO Steve Phillips said.
“The very nature of a changeover at the helm of a national team brings with it the possibility for change and evolution elsewhere in the backroom staff.”
Gatland will also be bringing in new blood after releasing Stephen Jones and Gethin Jenkins from their positions as attack and defence coaches respectively.
Phillips added: “I know both Stephen and Gethin understand this part of the process and they should be commended for the good grace with which they have accepted the decision.
“We thank both sincerely for their dedicated services to Welsh rugby as senior men’s team coaches.”