The textile industry has demonstrated a keen interest in developing techniques that enhance the value of end products. A pivotal aspect of this endeavour involves the functionalization of articles, a process that introduces new characteristics without compromising the fundamental properties of fibrous materials. Among the numerous treatments applied to textiles, flame retardancy stands out as a significant concern. Cellulosic fabrics, being highly flammable, find application in various sectors, particularly in the domestic and clothing industries. Given their critical role in sectors where direct contact with humans is inevitable, health and safety concerns are paramount. In this study, we aimed to develop viable alternatives using highly crystalline and resistant materials, known as metal–organic materials (MOFs), to retard flame's action on cotton fabrics. Materials UiO-66 and MOF-808 were developed, compared, and integrated into the fabric using the Layer-by-Layer (LBL) technique, with the objective of enhancing the potential for flame-retardant functionalization of the fabric. The materials produced were characterized using scanning electron microscopy (SEM). The flame-retardant functionality of the fabric was verified using a flammability test method in accordance with European Standard EN ISO 15025:2002—Protective clothing—Test method for limited flame propagation. UIO-66 had a defined shape, as has already been seen in the literature. In consideration of the flame-retardant properties exhibited by cotton fabric in response to treatment with the two MOFs, the fabric subjected to UiO-66 demonstrated effective extinguishment of the flame, while the fabric exposed to MOF-808 exhibited failure to impede the progression of combustion and subsequent complete consumption. Consequently, this study proposed a promising alternative for the development of cellulose fabrics with flame-retardant properties, contributing to consumer safety and advancing the field of textile functionalization. Moreover, it demonstrates that the MOF structure can contribute to the flame-retardant effect of the fabric according to the material produced.