Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
I've studied Teemo a lot and i found out that speed attack is not what he needs.In fact What is the dangerous part at Teemo is "The poison" ... and that means Magical damage that's why i've chosen teemo fully AP.And a fully Ap teemo can reach @ 600 AP ...that means the poison will do more damage that if u attack him with speed and damage. And also when you are poisoning... u can just 1 shot and run :) the poison will do it's job ...in this way killing is NO PROBLEM.
Usualy i buy Mejai's Soulsteller first...if u get more gills or at least assists u get a lot of AP 20/kill and 10/assist ...and u can get up to 200 AP:D from just one item. Teemo is very fun in this way seeing youre enemies coming toward you and when u give 1 shot and then run ...and see his life lowering to half :D