McGregor, who joins Associated from AOL, where she was the executive director, international sales, will be responsible for all revenues across ANM's HomesandProperty.co.uk and This is Travel.
She will report to Mark Milner, ANM's group commercial director. Craig Newsome, ANM's head of campaign management, will report into McGregor.
McGregor has been at AOL since 2003 and before this was the vice-president of sales at Sportal. She has also held sales jobs at News International, Thomson Directories and Yellow Pages.
Milner said: "ANM has had a fantastic year commercially. We are delighted that Mary is joining us. She brings with her an extremely strong commercial background and is well equipped to grow the team and develop our relationships with advertisers to build on this year's success."
Associated Newspapers recently launched online versions of its national newspapers, including the Daily Mail. However, ad sales for these titles will not be part of McGregor's remit.