The appointment followed a roster agency battle for the parent firm, which is thought to have included Mischief and beauty specialist Halpern.
Unilever plans to consolidate PR for three Dove briefs - the master brand, product brief and personal care.
Dove had one of the highest profile toiletries campaigns in recent years - the Campaign for Real Beauty featuring non-models in ads.
Matt Burgess, Dove's brand building director, Skin, UK & Ireland, said: 'Given the important role PR plays for Dove and the ambitions we have for 2013, we were looking for an agency to deliver a fresh and creative response to the brief.
'Crucially, as we plan to consolidate the Dove master brand, product and care briefs, we were looking for an agency that could bring the plans together to talk about the brand holistically in a consistent tone of voice.'
GolinHarris International president Matt Neale said of the 'ultra-competitive pitch': 'Dove is a brand that transcends its category.
For years, marketers around the world have sought to copy its pioneering work.' GolinHarris will start work this month.
Lexis also lost Unilever's lucrative Flora pro.Activ account to GolinHarris earlier this year, though Lexis is understood to retain work with the remainder of Flora's UK PR business.
It has also emerged that Unilever has handed its Sure Women deodorant brief, previously held by Lexis, to Mischief in recent weeks.
Lexis remains on the Unilever roster, working on the Vaseline, Sure Men and Slim.Fast brands, among others.
Jason Gallucci, MD of Lexis, said: 'We had nine great years working on Dove and wish the team all the best. The point of a roster is to rotate work around a select group of agencies to keep things fresh and this is how Unilever has worked for a long time.'