The objective of this study was to investigate the effect of carcass weight on chemical characteristics and fatty acid composition of m. longissimus dorsi and m. semimembranosus of European wild boar (Sus scrofa scrofa) meat. The research was carried out on 50 wild boars shot during four battues at hunting reserves in the central part of Poland. The carcasses were divided into three groups: ≤30 kg (G1), 31–45 kg (G2), and >45 kg (G3). The protein concentration increased with carcass weight (P ≤ 0.01). The concentration of saturated fatty acids was influenced by carcass weight and was higher when weight increased. A significantly higher level of monounsaturated fatty acids (MUFA) was found in the carcasses of wild boars from G3 compared with G1 group (P ≤ 0.01). The content of C18:2n-6 was significantly lower in the lightest carcasses compared with the heaviest (P ≤ 0.05). Statistical analysis confirmed that carcasses weight significantly affected polyunsaturated fatty acids (PUFA) n-3 content. The lightest carcasses contained a significantly higher concentration of PUFA n-3 (P ≤ 0.01). In addition, in G3, the amount of C22:5n-3 was two-fold lower (P ≤ 0.01) than in G1. The research has shown that the meat quality was affected by the carcass weight, resulting better parameters in the lighter than in the heavier carcasses. Therefore, most of the culled wild boars should be squeakers and young boars after the first year of life.