This disclosure is directed to lighting diffusing fibers (LDFs) having a flame retardant coating thereon. The LDFs comprise a glass RAL fiber core having a primary polymer coating of a clear, colorless polymeric material having an index of refraction less than that of the glass fiber core and a flame retardant coating applied over the primary coating. The flame retardant coating consist of approximately 35-85 wt. % UV curable polymer forming monomers and 15-65 wt. % of an inorganic, halogen free filler, along with at least one photoinitiator and an antioxidant. In an embodiment phosphor-containing polymer layer can be applied between the primary coating and the flame retardant coating. In another embodiment the phosphor can be added to the flame retardant coating.