Effect of utilizing both internal reflectors and fins on the productivity of solar still for several months has been experimentally and numerically studied. Accurate theoretical describing single sloped solar still integrated with fins and internal reflectors is developed. The effect of fins shadow is considered. Accurate calculations of solar radiation absorbed by the basin water and basin liner are performed considering solar path diagram and hourly variation of beam radiation falling on tilted surfaces. The performance of solar still is estimated under the Jordan weather conditions. The developed model is validated experimentally and found in great agreement with experimental work. The simulation results of this study show that adding internal reflectors at three sides of solar still (south, east and west reflector) increases the efficiency about 13%, 20%, 28%, 33%, 37% and 46% in June, April, September, October, January, and December respectively. While the average monthly efficiency increase and the average monthly productivity increase are 29.1% and 3.014 L/day.m(2) respectively. Furthermore, the results show that there is no significant effect on daily water output and basin water temperature when adding fins alone. Finally, adding internal reflectors with fins together, tremendous increase in both productivity and efficiency is achieved.