Her nomination was formally approved at a meeting of the full Council on Wednesday and she takes over from Cllr James Mills who has held the position for five years.
Cllr Mead was previously Cabinet Member for Health and Leisure and has held the District Council seat for Carterton South since 2018.
Until last week she was Mayor of Carterton, a position she had held for 18 months and she remains a town councillor for the Milestone Ward.
Cllr Mead said: “It is a great honour to be voted in as Leader and I would like to thank my predecessor, Cllr Mills, for his leadership and dedication to the residents and businesses of West Oxfordshire for the past five years.
“Under my leadership we will keep developing a strong economy, tackle climate change, promote health and fitness through our leisure centres and continue our efforts to provide affordable homes.”
At the Council meeting, Cllr Mead also unveiled her Cabinet including new additions Cllr Suzi Coul (Health and Leisure) and Cllr Merilyn Davies (Communities and Housing)
The remaining members are:
Cllr Toby Morris (Deputy Leader and Resources); Cllr Norman MacRae (Environment); Cllr Jeff Haine (Strategic Planning) and Cllr David Harvey (Climate Change).