An aluminum alloy wire, an aluminum alloy twisted wire, a covered wire, and a wiring harness, which are excellent in impact strength when a terminal fitting is connected. An aluminum alloy wire contains 0.03% or more and 1.5% or less by mass of Mg, 0.02% or more and 2.0% or less by mass of Si, and 0.1% or more and 0.6% or less by mass of Fe, with the balance consisting of Al and impurities; the wire containing acicular-shaped Mg2Si precipitates of 2.0 to 6.0 in aspect ratio. Further, provided are an aluminum alloy twisted wire containing a plurality of the aluminum alloy wires; a covered wire containing a conductor containing the aluminum alloy wire, and an insulation coating covering the outer circumference of the conductor; and a wiring harness containing a terminal fitting attached to the conductor of the covered wire.