Renowned for their high-quality meat from autochthonous breeds like the Iberian and Bísaro pigs, extensive pig farms prioritize animals’ welfare as a crucial factor in maintaining meat quality. In these systems, pig welfare results from the importance of providing abundant space, allowing for the full expression of the species’ behavior, and proper care. Immunocastration is a tool that might positively contribute to enhancing pig welfare and also provide a practical solution for managing male pig reproduction in extensive production systems. Immunocastration eliminates the need for surgical castration, such as avoiding the need for pain control, reducing potential post-surgical complications, and mitigating stress-related issues. Immunocastrated pigs exhibit improved behavior and feed efficiency. The desirable meat quality attributes of entire males are kept, while avoiding the boar taint issues, enhancing consumer acceptance and marketability. Through the application of immunocastration, extensive pig producers can achieve improved production efficiency and profitability while simultaneously addressing animal welfare concerns and meeting consumer preferences. In addition, immunocastration helps minimize the environmental impact of pig farming by decreasing nutrient runoff and waste pollution, promoting sustainable and ethical farming practices. This chapter intends to discuss the contribution of immunocastration to welfare improvement in non-industrial long-cycle extensive pig systems.