Updated the guide with new masteries, and uploaded detailed jungling routes, enjoy!

Decided to remove Wit's end from recommended. Not a bad choice, but I've decided it doesn't give enough defense to get an AS item with no crit, when that is where most of olaf's late game damage is going to come using this guide (75% crit with elixir)

**UPDATED ITEM BUILD ORDER TO BE MORE DETAILED/SPECIFIC OF A TYPICAL GAME

THANKS FOR ALL THE UPVOTES EVERYONE! I REALLY APPRECIATE IT. A FEW MORE % AND I'LL BE THE NUMBER 1 OLAF BUILD :)

Hey Guys,
This is the first guide I've written, so here goes. I've considered Olaf my main for a while now, and have tried several effective builds and have narrowed down the build that works almost all the time, regardless of enemies. This guide works well on both TT as well as SR. I originally created this guide as a 3s build, but as I play mostly Summoners Rift now, I'm updating it to be a 5v5 jungler build. All items and runes are updated for SR jungling, and I will soon add detailed jungling route information.

This Olaf build will result in an extremely tanky melee dps who still throws out crazy damage. Notice that by level 18 my armor and magic resist are both about 120. Let's get down to the details shall we?

Notice the three Olaf Games
^^quadra kill ftw :P

I do armor pen marks, simply because they are a must on any physical dps, armor seals, attack speed glyphs, two hp quints, and one attack speed quint. I've found that this combination allows olaf to have fast attack speed to regain hp early in jungling, as well as a bit of tankiness in case you need to fight their jungler early.

I've also experimented with attack speed marks before which worked well too. Note - the only reason that is viable is because Olaf gains armor pen passively from his ult (and the updated masteries which allow 10%), you need the arpen on other melee physicals.

Updated 11-22-2011 with New Mastery Recommendations

I go 21-9-0 in the new masteries, reasons below:

Ever since they released the new masteries I've tried out several different configurations, and ultimately have decided the changes have largely helped junglers, making it more easy for them. Ironically, if you go the vampiric olaf route, it is slightly slower since you no longer lose as much hp, which slows your attack speed...but it is still fast.

I dont take the 2 points Butcher (2/4 damage to minions) as many junglers do, I just think there are more viable masteries. Instead I finish the critical tree, get the 3% lifesteal, 10% arpen, and the final point in offense. I then use the remaining 9 to get bladed armor in defense, as well as a few points in health.

Ok let's get down the most important part. Item choices and build order.
This guide has no been updated to show my latest trends of jungling in the current meta game.

There are two viable options for starting items on Olaf, armor/pots and vampiric scepter. Recently I've been favoring vampiric scepter, since it gives Olaf the fastest jungle in the entire game, with no exceptions. I usually hit level 5 when mid is 4. I sometimes start ganking before 5, depending on how the lanes are going. The only disadvantage is do to the nature of jungling with vampiric scepter, you are often low hp during the first 3 levels.

My next item I buy is boots, then I finish wriggles. I buy merc treads because I think they are a must-buy for any melee dps. I then build frozen mallet for some health, a zeal for the as, and runspeed, as well as the bonus crit. Once those two items are done I build atmas, unless they have a fed caster, where I would go banshees veil. If they do not, I finish phantom dancer, at which point you have crazy crit percentage between phantom and atmas. I then either finish banshee veil or wait until I can sell wriggles and afford a bloodthirster.

I have two pictures with the two routes I take, depending if I start with vampiric scepter or armor and pots.

Vampiric Scepter (Speed) :

If you do it correctly, and back after blue, the twin golems should respawn just about when you are getting back, allowing you to jungle at the maximum speed. Notice I don't usually gank on my first run through if I'm speed jungling as I'm usually lower hp until I go back once.

Cloth Armor and Pots:

With the buff to masteries/jungling, it is super safe to jungle with cloth armor on olaf, you dont even lose much hp, therefore I like to aggressively gank. I lik to start double golems and then gank top if you are on that side, and if not I do golems, wraiths and then mid. Bot lane is usually tough to gank very early as olaf.

Ganking is all about timing. You should keep an eye on which lanes are playing more aggressively, as well as when solo lanes blow their flash. I like to gank mid at level 3 or 4 simply to get them to use their flash, then I come back in a level or 2 for the kill. Top lane is my favorite lane to gank as Olaf. If you have ghost up and your top lane is relatively competent, it's a very easy gank. Even if they have flash up you can usually still get the kill if you have red and ghost and they are slightly overextended.

What your job is in a teamfight is fairly straightforward. Talk to your team and agree which champion on the opposing team is most dangerous (whether it is their AP carry or physical carry). Then wait for the teamfight to start, turn on your ult (BEFORE YOU GET FOCUSED DOWN--THIS IS IMPORTANT). You want to use your ult pretty much as soon as the teamfight starts even if you aren't getting focused. So you pop your ult, pop ghost, and immediately take our their carry. There is no way to slow or disable you and you should be able to take out their carry before their team even gets you to half health. Remember to use Vicious Strikes as soon as you get in melee range, and reckless swing on the person you are focusing. You'll find if you are doing fairly well in the game and have your ult up you can 2v1 almost any 2 characters in the game (if they aren't fed), using your ult and your natural life steal (take down the squishy person first).

Well I believe that's it. I'm sure I forgot a couple things that I can update after this get's published, so I'll keep an eye on this. I welcome comments or even criticisms (constructive ones are preferred) and I'm open to debate whether there is a better build option with Olaf, I look forward to your comments.

jm1llz