A fire resistant (FR) pressure sensitive adhesive (PSA) comprises a blend of: a) a (meth)acrylate polymer comprising cationic monomer units; and b) a non-halogenated flame retardant. In some embodiments, the cationic monomer units comprise cationic quaternary amine groups. The (meth)acrylate polymer may additionally comprise anionic monomer units, in which case the molar ratio of anionic monomer units present in the polymer to cationic monomer units present in the polymer is typically less than 0.9. The FR PSA may be aqueous based and may be free of common solvents. The FR PSA may demonstrate improved flame retardance with good compatibility between PSA and flame retardant, and may retain compatibility even at high loadings of flame retardant.