Gale, who currently holds the position, is to leave the media company at the end of the year to relocate to Switzerland with her family.
She joined the outdoor advertising company in 2007 to head up marketing communications and branding.
The company is currently recruiting to find a direct replacement to fill the role which is responsible for building brand awareness and international marketing activity.
Prior to joining CBS, Gale was European CEO at agency The Marketing Store and has held positions at Saatchi & Saatchi, Grey and OgilvyOne.
In August CBS announced Antonio Alonso would replace Clive Punter as international chief executive reporting to Leslie Moonves.
Like its competitors, CBS Outdoor has been struggling with revenues during the recession.