The objectives of this experiment were to investigate the effect of feeding frequency and oil supplementation to the diet on performance and feeding behavior of lactating dairy cows. Twenty 4 lactating Holstein cows, 12 primiparous, (BW = 626 ± 58 kg and DIM = 195 ± 44 d) and 12 multiparous, (BW = 617 ± 25 kg and DIM = 207 ± 39 d) were randomly assigned to the 4 diets contained 2.5 percent supplemental oil or no oil and feeding frequency of 3 or 1 time per day in a randomized complete block design with a 2 × 2 factorial arrangement. Frequency of feed delivery and oil supplementation had no effect on dry matter intake. Oil supplementation reduced slug feeding especially with feeding once per day (P < 0.05). Feeding frequency and oil supplementation interaction tended to significant for milk yield (P = 0.09), as there was a numerical increase in milk yield in 3 time feeding with oil diet. The cows fed oil diet in 3 time feed delivery had lower milk protein (P < 0.05), but milk fat increased with 1 time feeding and oil supplementation (P < 0.05). The results showed that oil supplementation to mid lactating cows diet can decrease compromised effects of decreasing feeding frequency.