Barnweill Church or Barnweil Church (NGR NS 40506 29903) is a ruined pre-reformation kirk situated on rising ground on the slopes of Barnweill Hill, Parish of Craigie, South Ayrshire, Scotland; about 3 km from Tarbolton. The church was known locally as the "Kirk in the Wood". It lies about 170m North North-East of Kirkhill Farm. Barnweill was central to the Protestant Reformation in Ayrshire through its association with John Knox.