Halogen-free flame retardant compositions exhibiting flame retardance and retention of mechanical properties, especially elongation at break, upon long-term high temperature exposure and comprising a) at least one copolyester thermoplastic elastomer, and b) from at or about 1 to at or about 30 weight percent, based on the total weight of the composition, of at least one flame retardant comprising a phosphinate, diphosphinate and/or polymers of these; c) from at or about 0.25 to at or about 15 weight percent, based on the total weight of the flame retardant composition, of one or more polyhydroxy polymers having a number average molecular weight of at least 2000 and selected from the group consisting of ethylene vinyl alcohol copolymers and poly(vinyl alcohol)s.