The North Down MLA was elected unopposed by party delegates at an Alliance Party Council meeting held in Bangor. He succeeds Naomi Long MLA, who became Party Leader on October 26.
Dr Farry was first elected as Alliance MLA for North Down in 2007 and served as Minister for Employment and Learning between 2011-2016. He has previously served Alliance as General Secretary and a Councillor in North Down,.
Speaking about his election, Stephen Farry said: “I am delighted to receive this endorsement from the Alliance membership. Alliance is a party on the rise, with clear liberal and progressive values and a strong vision for an open and inclusive Northern Ireland.
“With Naomi, we have a powerful communicator and is set to take Alliance to the next level. For the past number of years, Alliance has had a strong team of elected representatives in the Assembly and elsewhere. My role now is to build on this foundation and to share in publicly advocating the Alliance vision, values and policies, and providing support in a range of internal functions.
Alliance Leader Naomi Long MLA said Dr Farry would bring an expertise to the role.
“I congratulate Stephen on his election as Deputy Leader and know he will bring the same dedication and professionalism to the position as he has every other role he has undertaken.
“He was also recently appointed Alliance Brexit spokesperson and I know he has the expertise needed to help drive Alliance forward.”