Recently, we hung an Italian-flag windsock on our deck as a prop for an upcoming party and realized that the colors of Italian flag looked a lot like the Mexican flag on first glance. (A neighbor dutifully noted the windsock and commented that she was surprised because we were not “windsock” people.)
So what are the differences between the Italian and Mexican flags? The Italian flag is a vertical tricolor (in Italian Il Tricolore) of green, white, and red. The Mexican flag on first glance is the same except the there is a coat of arms in the center white stripe. However, there are a couple of subtle differences. The Italian flag uses lighter shades of green and red and the Italian flag has an aspect ratio (width:height) of 3:2 while the Mexican flag is 7:4.
The meaning of the colors for the Mexican flag likewise is not fixed, but can be taken to mean roughly: green = hope, white = purity and red = blood of national heroes (as pointed out by several comments below, in particular the comment August 26, 2017 at 5:53 PM).

If you are into more similarities, a few pointed out in the comments, there are also these:
- Monaco / Indonesia flag similarity
- Romania / Chad flag similarity
- Mali / Senegal flag similarity (very similar are Guinea and Cameroon)
- Netherlands / Luxembourg flag similarity
- New Zealand / Australia flag similarity
- Slovenia / Slovakia / Russia flag similarity
- Ecuador / Columbia Venezuela flag similarity












