In this study, the relationships between total length and opercle dimensions (length and height) of European perch inhabiting Lake Ladik were examined. Sampling was carried out between January and February 2010. A total of 110 individuals were sampled and total length ranged from 11.6 to 24.7 cm. Opercles were extracted for all fish caught. Opercle length (OL) and height (OH) were measured discriminating the right and left of each pair of opercle. OL and OH ranged from 10.04 to 24.32 mm and 9.23 to 20.67 mm, respectively. Total lengthopercle length and total length-opercle height relationships were calculated separately for right and left opercle. The results of statistical estimates indicated that the linear model had higher regression coefficient than the power model for both relationships. The regression coefficients of the total length-opercle length and total length-opercle height regression equations were 0.951 (p< 0.001), 0.936 (p< 0.001), respectively. When right and left opercles were compared, we found that there was significant distinctness in terms of opercle length (p< 0.001) but there was no significant difference in terms of opercle height (p> 0.05).