**Abstract**

Lignocellulosic fibers from *Opuntia* biomass, family Cactaceae, were mainly studied for their sustainability and cellulose content richness. This chapter highlights the current exploitation of *Opuntia* (Cactaceae) as potential feedstock for value-added applications such as reinforcement in composites and paper manufacturing. Cellulosic fibrous network fractions were isolated from different plant parts, and their fundamental properties, chemical and structural compositions, were analyzed, and the obtained results were discussed. The obtained fibrous networks were incorporated into two thermoplastic polymers; their enhancement properties and biodegradability have been studied. However, different recent methods of cellulose fiber extractions (pulping) and paper manufacturing have been investigated by testing two procedures of delignification: chemical and semichemical pulping process; these operations were followed by fibrous suspension characterizations and paper productions. The obtained results show the suitability of *Opuntia* (Cactaceae) for the new trend in ecological and green materials.

**Keywords:** *Opuntia*, fibrous networks, chemical composition, composites, pulping
