Dose-dependent effects of a palmitic acid-enriched fat supplement (PA; 87% C16:0; Bergafat F-100) on total-tract digestibility responses of dairy cows were evaluated. Low and high basal dietary fatty acid (FA) diets (LF: 2.2% DM and HF: 3.5% DM) were used as a split-plot to determine relationships between basal dietary FA content and PA dose. Sixteen Holstein cows (149 ± 56 DIM) were assigned randomly to treatment sequence within basal FA groups. PA was supplemented at 0, 0.75, 1.50, or 2.25% of ration DM in a 4 × 4 Latin Square design within each basal FA group. Periods were 14 d with the final 4 d used for data collection. FA content of LF and HF diets was achieved by altering the proportion of soyhulls and cottonseed in diets. The statistical model included the random effect of cow and the fixed effects of basal FA group, PA dose, period, and their interactions. Linear, quadratic, and cubic contrasts were used to determine effects of PA dose. Compared with HF (with cottonseed), LF diets (with soyhulls) increased NDF digestibility (50 vs. 48%; P < 0.01). PA dose also increased NDF digestibility (46, 50, 51, and 52%; linear P < 0.01). There was a tendency for an interaction of treatments (P = 0.12) as NDF digestibility increased more for HF with increasing PA than for LF. Compared with HF, LF diets decreased 16-carbon FA digestibility (65 vs. 71% P < 0.01) and tended to increase 18-carbon FA digestibility (85 vs. 82%; P = 0.07). PA dose decreased 16-carbon FA digestibility (76, 67, 64 and 64%; quadratic P < 0.01) and increased 18-carbon FA digestibility (82, 83, 85 and 85%; linear P < 0.05) for 0, 0.75, 1.50, and 2.25% PA, respectively. PA dose linearly decreased the digestibility of total FA in LF diets (81, 76, 73, and 71%) but did not in HF diets (77, 76, 76, and 76%; interaction P < 0.05) for 0, 0.75, 1.50, and 2.25% PA, respectively. HF diets increased total FA absorbed compared with LF diets (0.94 vs. 0.71 kg/d; P < 0.05). Additionally, PA dose increased total FA absorbed (0.64, 0.77, 0.90 and 0.97 kg/d; linear P < 0.01) for 0, 0.75, 1.50, and 2.25% PA, respectively. In conclusion, the total-tract FA digestibility responses to PA dose were affected by the FA content of the basal diet.