This  study investigated the discharge coefficient in asymmetric rectangular labyrinth weirs. A dimensional analysis was carried out which showed that the discharge coefficient is a function of dimensionless parameters, such as the ratio of asymmetric widths of left and right cycles (wL/wR), the ratio of the total hydraulic head to the weir height (Ht/P), and the weir length ratio (B/wavg). The experimental results for the discharge coefficient were found to decline as wL/wR increased or B/wavg decreased. For wL/wR = 1.19, the ratio B/wavg = 2.76 improves the discharge coefficient by nearly 12.7% compared to B/wavg = 3.1. For wL/wR = 1.42, the ratio B/wavg = 2.76 improves the discharge coefficient by nearly 34.2% compared to B/wavg = 3.1. For wL/wR = 1.70, the ratio B/wavg = 2.76 improves the discharge coefficient by nearly 30% compared to B/wavg = 3.1.