Amazonian fibers are gaining attention for their potential use as sustainable materials in construction due to their natural abundance, renewability, and eco-friendly properties. However, their application often depends on understanding their intrinsic properties and how NaOH treatment can modify them. This study focuses on characterizing the Tucum, an Amazonian fiber, evaluating its physical, chemical, and mechanical properties, and assessing the effects of different treatments. The untreated fiber and its treated counterparts underwent a series of analyses, including thermal, structural, and morphological evaluations. The results demonstrated that it was possible to characterize several key properties, such as tensile strength, thermal stability, and water absorption. Moreover, significant changes were observed in the fiber's structure and behavior after treatment, highlighting the influence of the applied process. These findings provide valuable insights into optimizing natural fibers for construction applications, promoting their broader use in sustainable engineering practices.