Heat stress affects a plethora of pork production variables, in part stemming from a reduction of feed intake. The experimental objective was to investigate the effect of heat stress on the pig’s response to dietary fat in terms of growth performance and digestibility over a 35 d finishing period. A total of 96 barrows were randomly allotted to 1 of 9 treatments arranged as a 3 × 3 factorial with the main effects of environment [thermonetural (TN), pair-fed thermoneutral (PFTN), or heat stress (HS)] and diet [a corn-soybean meal based diet with 0% added fat (CNTR), or the CNTRL with 3% added tallow (3%TAL), or 3% added corn oil (3%CO)]. Pigs were individually housed to record intake. Fecal samples were collected on d 17 (~ 114 kg). No significant interactions between environment and diet were observed (P > 0.100). HS decreased ADFI (27.8%; P< 0.001), ADG (HS = 0.72, TN = 1.03, PFTN = 0.78 kg/d; P < 0.001), and G:F (HS = 0.290, TN = 0.301, PFTN = 0.319; P = 0.006). G:F but not ADG or ADFI tended to increase with added fat (CNTR = 0.292, 3%TAL = 0.303, 3%CO = 0.314 g/100 g; P ≤ 0.073). Environment had no impact of TTTD of AEE (P = 0.118). In summary, HS decreased ADFI, ADG, G:F and ATTD of AEE, but had no significant impact on TTTD of AEE. Therefore, the pig’s response to dietary fat source is not different in heat stress conditions as compared to thermoneutral conditions.