Abstract: A filled thermoplastic olefin composition comprising (a) a first polypropylene having (i) substantially isotactic propylene sequences, (ii) a narrow molecular weight distribution, and (iii) a broad composition distribution, and (b) at least about 20 percent by volume filler based on the total volume of the composition. Optionally, the composition can comprise a second polypropylene different for the first polypropylene, both polypropylenes preferably propylene/?-olefin copolymers. The filler can be organic or inorganic, and the compositions are useful as, among other applications, protective coverings for wire and cable.