Hilary Sykes is stepping down from the board of Pendragon.
Sykes, the dealer group's corporate services director, has announced plans to retire on December 31.
She became a director in 1999 after joining Pendragon as company secretary in 1994, prior to which she was a corporate lawyer with Geldards.
Sykes said: "It has been a privilege to work with such a talented and dedicated team at Pendragon, through a period of substantial growth and change. I wish the board and all the team continuing success for the future."
Mel Egglenton, Pendragon chairman, added: "I would like to thank Hilary for her time on the Board and for her significant contribution during 22 years with Pendragon.
"On behalf of the whole board I extend our gratitude and our very best wishes to Hilary."