The selectivity of fishing gears plays a pivotal role in shaping the dynamics of aquatic ecosystems and fisheries sustainability. Through a comprehensive examination of trawl nets, gill nets, and longlines, this paper delves into the factors influencing selectivity, including gear design, selectivity criteria, selectivity terminologies, selection curves, and impacts. Drawing upon scientific research, empirical evidence, and case studies from around the world, this paper highlights the effectiveness of different selectivity measures in balancing the extraction of target species with the conservation of non-target species and habitat integrity. By synthesizing current knowledge and emerging trends in fishing gear selectivity, this review paper offers valuable insights for policymakers, fishers, scientists, and conservationists striving to navigate the complex interplay between human exploitation and ecological resilience in aquatic environments.