Chris Coleman's side are 12th after they reached the semi-finals of Euro 2016, but England are 13th after exiting in the last 16 to Iceland.
The Republic of Ireland are 23rd in the standings, Northern Ireland are 32nd and Scotland are 67th, meaning Gordon Strachan's side rank below the likes of Benin and Panama.
Argentina are ranked number one with Brazil second and Germany third.
Top 20: 1 Argentina, 2 Brazil, 3 Germany, 4 Chile, 5 Belgium, 6 Colombia, 7 France, 8 Portugal, 9 Uruguay, 10 Spain, 11 Switzerland, 12 Wales, 13 England, 14 Croatia, 15 Poland, 16 Italy, 17 Costa Rica, 18 Mexico, 19 Peru, 20 Ecuador
Wales will end 2016 ahead of England in the Fifa world rankings.