Graphical AbstractSummary:Limited information exists about the effect of drought stress on forage fiber digestibility. In a greenhouse, we evaluated the effect of drought stress on neutral detergent fiber (NDF) digestibility of corn tissues. Corn plants were subjected to abundant (598 mm) or restricted (273 mm) irrigation regimens, and stems and leaves were incubated in the rumen of dairy cows. According to the conditions of this study, we concluded that drought-stressed corn had a marginal increase in NDF degradability of leaf blades but not in stem internodes, that drought stress had no effects on the effective ruminal degradation of NDF when comparing irrigation treatments within hybrids, and that the effect of drought stress on NDF degradability of corn for silage is still inconclusive. We also observed that the growth of corn plants in a greenhouse does not result in plants with the anatomical structure typically seen in the field.