I was told that the surname originates from Waulker, which has something to do with cloth (don't ask me what) The Highland version of the name for some reason is MacNucator. Supposedly the majority of the clan changed their name to Walker sometime in the early 18th century, but historians seem to connect them to the Macmillans located in the Knapdale area. I suppose they don't have an authentic tartan of their own because it's been a somewhat convoluted liniage. I know many of my Walker relatives wear the Macmillan tartan.