Doum is a type of palm tree having leaves with a lower surface (looking like palm leaves) and trunk with relatively reduced height (< 1 m). It is naturally growing in a wide range of conditions and tolerating extreme temperatures (36–38 °C). In this work, doum leaves fibers and doum trunk fibers were identified as potential sources to produce cellulose derivatives, namely cellulose microfibers (CMFs) and cellulose nanocrystals (CNCs). CMFs were obtained from the identified sources via chemical treatments and then subjected to sulfuric acid hydrolysis to produce CNCs. The studied materials were characterized at different stages of treatment. It was found that CMFs, extracted from both sources, exhibited a uniform size with a microfiber diameter ranged from 3 to 10 µm and crystallinity between 80 and 76%. The as-produced CNCs showed the same characteristics with an average diameter of 5.3 nm, an average length of about 450 nm and a crystallinity of 90%. This study can draw the attention of researchers towards doum tree as a new source of cellulosic materials. Owing to their excellent characteristics, the produced CMFs and CNCs could be used as additives or reinforcing agents for polymer composite development and beyond.