This study examines the harvest function and factors of technical inefficiency in Turkish large-scale marine fisheries, using data from the TURKSTAT Fisheries Statistics Micro Data Set. The main purpose is to incorporate bioeconomic modeling into technical efficiency analysis by estimating a stochastic frontier harvest function that considers both fishing effort and stock biomass. Through inefficiency effects model, the influences of vessel attributes, gear types, fishing areas, and technological instruments on the technical inefficiency of fishing units are investigated. The results indicate that fishing efficiency is influenced by gear type, regional practices, and the accessibility of specific technologies. Specifically, environmentally unfavorable methods like bottom trawling are demonstrated to be less efficient than other techniques. Additionally, Turkish fisheries are experiencing diminishing returns to both effort and stock, underlining the need for more rigorous effort reduction policies and adaptive quota regulations, particularly for economically essential species. Moreover, the results provide guidance for improving fisheries management policies in Türkiye and highlight the importance of balancing efficiency and sustainability through enhanced regulation of fishing practices, technological advancements, and regional management approaches.