The objectives of this work are twofold. We firstly aim to measure the technical, allocative and economic efficiencies for a total sample of 232 cereal farmers in sub-humid region in the North of Tunisia using a Stochastic Frontier Analysis (SFA) Approach. The Second objective is to identify the determinants of the calculated farms efficiency. Results of the SFA model show that average of technical, allocative and economic efficiencies are respectively 85%, 84% and 72%. By operating at full economic efficiency levels, the sampled farms would be able to reduce their costs of wheat production with around 28%. Pure technical efficiency, scale efficiency, and allocative efficiency levels account respectively for 15 %, 16% and 28 % of the total cost reductions. Results of the Tobit regression indicate the positive effect, on economic efficiency, of variety choices, types of seeds, the importance of cereals in the production system and farm size. This suggests that there is potential to improve production efficiency through aggregating farmers into farmer's cooperatives in addition to the controls of input prices.