In this paper, an oblique side weir was studied by nine models installed at the entrance of side channel at an angles (300,450,600,750 and 900) respected to side channel wall and installed at two directions, with flow direction and opposite it. The models were tested by five different flows passing over them so, the number of runs is 45. The hydraulic characteristics of flow over vertical and oblique side weir were studied, and the results show increasing of discharge over side weir when installed at an oblique direction and the average increases when their inclination at left direction was greater (6%) than that right direction. Equations were predicted for calculation of discharge coefficient (Cd) and coefficient of energy loss (k) for two directions and the water surface profile for vertical and oblique side weir in two directions is plotted.