The purpose of this research is to investigate the effect of potassium fertilization source and dose on productivity and quality parameters of strawberry. The trial was conducted in 2016-2017 at the experimental greenhouse of Hassan II Institute of Agronomy and Veterinary Sciences in Rabat. Strawberry plants of the cultivar "San Andreas" were planted on November 6 th in 12 liter pots equipped with a gravity fertigation system. The experimental design was a split-plot with eight treatment combinations of two potassium fertilizer sources: 1) Potassium Sulphate for the whole growing cycle (PS/PS); 2) Potassium Nitrate during the vegetative period and Potassium Sulfate during the fruit production period (PN/PS) and four potassium fertilizer doses: 100, 200, 300 and 400 kg/ha of K 2 O replicated thrice. Potassium sulfate source was superior to potassium nitrate on the improvement of productivity and quality parameters of strawberry fruit. Potassium sulphate improved the number of flowers by 16%, fruit production by 21%, sugar content by 3%, and titrable acidity content by 0.5 g/L. The highest yield was recorded in plants receiving 300 kg/ha K 2 O as potassium sulphate. The 300 kg K 2 O/ha dose gave also superior results regarding quality parameters of strawberry fruit. This optimum potassium dose enhanced number of flowers by 35%, fruits produced by 44%, sugar content by 25% and titrable acidity content by 0.9 g/L.