<p>Labyrinth weirs are a type of non-linear weir known for their higher discharge coefficient compared to similar structures. Investigating methods to increase the discharge coefficient and energy loss in these high-efficiency weirs has garnered a significant attention in recent years. In this study, eight sinusoidal labyrinth weirs with varying heights and effective crest lengths were analyzed to examine their discharge coefficient and energy loss. The results indicated that increasing the flow rate or the upstream flow depth leads to a decrease in both the discharge coefficient and energy loss. Conversely, increasing the effective length of the weirs resulted in higher discharge coefficients and greater energy loss. Additionally, an increase in the ratio of the inlet opening width to the outlet opening width led to an increase in both discharge coefficient and energy loss. Maximum energy loss is observed at width ratios of the inlet to outlet openings of 4.60 and 7.67, due to the higher flow rate and increased jet power and hydraulic jumps. Furthermore, higher weir heights were associated with increases in the discharge coefficient and flow energy loss. A 20% increase in weir height results in a 19.8% average increase in energy loss, due to the greater height of falling jet and more significant flow dissipation. The use of flow splitters on the crest weirs showed a decrease in the discharge coefficient and an increase in energy loss. Finally, the study presents equations for calculating the discharge coefficient and flow energy loss with high correlation coefficients.</p>