A better understanding of farmers' behaviour regarding agri-environment schemes (AES) can be one step towards further improving the schemes. To assess farmers' acceptance and perception of AES, the 'Theory of planned Behaviour' (TPB) was applied to identify factors influencing farmers' willingness to join AES. In a region in England, standardized face-to-face interviews were conducted with 32 farmers already participating in AES. The results show that the general attitude and acceptance of the scheme were high. Biodiversity, landscape, and natural resources were perceived to be improved by the scheme and to be valuable. An increase in weeds was perceived as an undesirable outcome. Farmers' families were ranked to have the highest and most positive social pressure on farmers' decisions to join AES. More paperwork and higher prescriptions would make it much more difficult to join the scheme. Environmental advice and generally more consideration of environmental conservation in policy were perceived to make the joining easier.