Tilapia (Oreochromis niloticus and related species) are the world's second most farmed fish, with global production exceeding 6 million tonnes annually. Despite their economic significance, tilapia welfare science is significantly underdeveloped. Tilapia are sentient vertebrates demonstrating nociception, stress responses (cortisol elevation during crowding), and social behaviour. Intensive pond and recirculating aquaculture system (RAS) production raises concerns about stocking density, poor water quality, and disease burden. Streptococcosis affects 50–80% of tilapia farms globally, causing meningitis, exophthalmia, and mortality. Welfare-positive production improvements include optimised stocking densities (<30 kg/m³ in RAS), water quality monitoring, and vaccination against Streptococcus. Slaughter methods — primarily CO₂ narcosis or live chilling — require welfare assessment and improvement. Welfare certification for tilapia is nascent but growing.