The present study investigated effects of virgin coconut oil (VCO; 7.0% C8:0, 5.4% C10:0, 48.9% C12:0, and 20.2% C14:0) and pine bark extract (PBE; 75% condensed tannins), either separately or in combination as supplements to a lactation dairy diet on in vitro ruminal fermentation profiles. The experiment was performed in a completely randomized design with 4 independent runs of continuous cultures. Four dietary treatments included: 1) control (CONT; TMR without supplement), 2) TMR with 3% VCO (VCOT), 3) TMR with 3% PBE (PBET), and 4) TMR with 3% VCO and 3% PBE (VPT). Each culture of 700-mL working volume fermentation content was offered a diet of 20 g DM/d in 2 equal portions at 0800 and 2000 h. The data in this study were analyzed using the Proc Mixed procedure of SAS using a model that included fixed effect of dietary treatments (CONT, VCOT, PBET, and VPT) and a random effect of fermentor within independent run. Culture pH was maintained at least at 6.13 across dietary treatments, and supplementing VCO and/or PBE did not influence culture pH. Total VFA concentration was similar in response to the supplements. Supplementation of VCO decreased acetate proportion, but did not affect propionate proportion, resulting in a tendency to decrease acetate-to-propionate ratio (P = 0.10). In contrast, PBE supplementation increased acetate proportion, while it did not influence propionate proportion, leading to a tendency to increase acetate-to-propionate ratio (P = 0.10). Cultures offered VCOT and VPT increased butyrate proportion (P = 0.01). Supplementing PBE decreased (P < 0.01) ammonia-N concentration both in PBET and VPT, whereas VCO supplementation resulted in no effect on ammonia-N concentration. Cultures offered VCO and PBE supplementation, either separately or in combination, showed no response on methane production, although feeding VCOT numerically decreased methane production by 13.5% compared with CONT. The decrease in ammonia-N concentration when PBE-containing diets (PBET and VPT) were offered is likely attributed to condensed tannins in PBE; however, their concentration would not be enough to lessen ruminal methanogenesis. In addition, the concentration of VCO used in this study may have not been enough to manipulate ruminal fermentation.