This study aimed to investigate the interactive effects of dietary starch concentration (220 or 420 g/kg DM) and supplementation with calcium salts of palm fatty acids (CSPFAs; 0 or 30 g/kg DM) on carcass characteristics and meat quality in lambs. Thirty-two castrated Dorper × Santa Inês male lambs (initial body weight 25.0 ± 2.85 kg) were randomly assigned to four experimental diets in a 2 × 2 factorial arrangement for 44 days. Although carcass yield remained unaffected (average 49.4%; p > 0.05), CSPFA supplementation significantly increased fat deposition, including perirenal fat mass (590 vs. 400 g; p = 0.005), renal fat score (2.90 vs. 2.66; p = 0.035), and subcutaneous fat thickness (3.8 vs. 1.9 mm; p = 0.017). A starch × CSPFA interaction (p = 0.014) was observed for carcass cooling, where high-starch diets reduced the 24 h temperature only in lambs not receiving CSPFA (7.45 vs. 8.48 °C; p = 0.028). CSPFA also altered the muscle fatty acid profile by increasing C16:0 and total saturated fatty acids (SFA) while reducing polyunsaturated fatty acids (PUFA). In conclusion, palm-oil–derived CSPFA enhances carcass fatness but compromises the nutritional value of lamb meat by promoting an unfavorable fatty acid profile.