Windsor was a 1970's-80's marque, a brand of Acer-Mex in Mexico. Most were made in Mexico, with some being made in Japan in the 1980's. Mid 70's Mexican versions were imported by Linder Euroimports.

This badge is a later version with the large W.

Note: The Windsor brand has apparently been dusted off in a licensing agreement and one can now find the name on bikes made in China.