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Abstract. Cannabis stalks/stems, which are generally considered as agricultural byproducts and discarded, constitute around 40-50% of the total plant biomass. These stalks possess significant untapped potential for sustainable resource utilization within the cannabis industry. This research explores the process of transforming cannabis stalks into cellulose nanocrystals (CNCs) through alkali, bleaching and metal oxidation treatments, and characterization of resulting materials at every stage of processing. A detailed biochemical analysis of the stalks and fibers indicated a lignocellulosic composition consisting of 57% cellulose, 17% hemicellulose, and 14% lignin. Cannabinoid analysis resulted that the raw cannabis stalks contained 0.078% (dry basis) total tetrahydrocannabinol (THC), complying with regulatory standards for processing by unlicensed users. To evaluate the effectiveness of alkali treatment in reducing residual THC, a mild pretreatment with 1-3% NaOH solution was applied. This treatment successfully decreased the total THC content from 0.078% to 0.036%, anticipating that higher alkali concentrations may further reduce THC levels, potentially yielding THC-free biomass. Subsequent processing involved a more concentrated 10% NaOH treatment followed by sodium chlorite bleaching step to produce cannabis-derived cellulose pulp. This pulp was then converted into CNCs through chromium (III) (Cr³⁺) metal-catalyzed oxidation method. The resulting alkali treated fibers, cellulose pulp and CNCs demonstrated a variety of functional groups. Thermogravimetric analysis (TGA) demonstrated that alkali and bleaching treatments improved the thermal stability of the biomass. X-ray diffraction (XRD) analysis revealed that the crystallinity index significantly increased from 50% in the raw fiber to 72% in the final CNCs product, indicating enhanced structural uniformity. Transmission electron microscopy (TEM) imaging confirmed the formation of well-defined spindle-shaped CNCs with an average length of 280 nm and a width of 9 nm, resulting in an aspect ratio of 34. These nanocrystals can be used for a wide range of industrial applications, including but not limited to reinforcement in bio-composites, bio-adhesives, bio-absorbent materials, sustainable packaging solutions, and edible food coatings. By converting underutilized cannabis waste into valuable nanomaterials, this study presents an innovative approach to resource optimization in the cannabis sector, contributing to the principles of a circular economy.