In this study, fibre morphology of microwave-treated oil palm trunks (Elaeis guineensis Jacq.) was studied. Thirty years old palm trunks (OPT) were selected, felled and divided into peripheral, middle and inner zones. Only the basal portion of the OPT was used to reduce variability of sampling. Microwave treatment of the OPT samples were conducted by using a domestic microwave oven operating at 2.45 GHz and with maximum rated power output of 950 watt. The samples were microwave-treated at four different power intensities of 950, 700, 500 and 300 watts and for four different exposure durations of 5, 10, 15 and 20 min leading to a total six varying combinations of power and exposure period. The untreated OPT sample was used for comparison purpose. The fibre length, fibre diameter, fibre lumens diameter, and fibre walls thickness were measured between each of the zones of the oil palm trunk in relation to the different microwave treatment. All microwave treated samples showed changes in the fibre with the combinations of microwave treatment with 700 watts power intensities with 15 minutes exposure durations produced the most stretched and elongated fibres. This findings could be useful in finding suitable techniques for processing the OPT into value-added products.