Not really, it's tolerated, the police look the other way but its not legal.
Coffeeshops are allowed to sell but they are technically not allowed to buy or grow large ammounts themselves so they are breaking the law by doing so. Also recently in the southern and eastern parts of the country registration is required to buy, and next year (unless they change their plans, which i think they might) you'll need a document with you to prove that you are a dutch citizen before you can buy it.