The invention provides a polyolefin composition comprising: A) a propylene-based polymer having a flex modulus of greater than 1500 MPa and an HDT of greater than 100° C.; B) an ethylene/α-olefin interpolymer having Tg of less than −30° C., a tan delta, measured at 0.1 radians/s at 190° C., of less than 3, an HDT that is greater than, or equal to, the peak melting temperature of the ethylene/α-olefin interpolymer, measured by differential scanning calorimetry; and C) a fiber filler; and D) a nitrogen source and/or a phosphorus source, wherein at least one source is derived from at least one organic compound, or salt thereof; and wherein the weight ratio of the propylene-based polmer:ethylene/α-olefin interpolymer (A:B) is from 9:1 to 6:4.