Galio is often overlooked in the League; I often find myself explaining what my abilities do to my hapless lane partner.
Galio is a force, able to turn around any team fight. He is able to bully your opponents in your lane, forcing them to cower at your turret under his relentless gaze.
My build emphasizes his ult; giving it more effects and doing more damage, while at the same time giving him a very good deal of survivability. I think it's a great build, and Galio is one of my favorite champs to play. Honestly, how cool is this flying badass?
I call this build Palio, cause he's your team's best friend.

Galio is a tank. That's how people play him, but this build gives him a deal of fighting power without sacrificing any defense.
He needs to be fearless, willing and able to take on a whole team and survive.
He is a counter-caster tank, shrugging off that puny Fiddlesticks' drain like it was nothing, and he's hugely disruptive to their whole team. You need to fly your little butt into the middle of everything and DISRUPT SOME ****!

Pros
-Great early game
-Lane bully
-Taunt; When is that not good???
-Great support
-Very hard to avoid
-Very fast
-Tough
-I can't remember a time when I've been killed late game. Honestly!
Cons
-(This is a biggie) People can walk out of your ult occasionally because of those new tenacity items
-He can get mana starved early
-Melee caster
-You're right in the middle of things
-Most people view him as a hard champion to play. While I agree, he's one of the hardest and most rewarding champions to master.

When laning as Galio, you need to bully off the other team from your creeps, not only for the benefit of your lane partner, but it's the only way for you to get in close to farm creeps. As such, mana regen is a problem for Galio. Being real aggressive early is a drag on your mana. Galio needs to take the brunt of their damage, he's the distraction and he needs to be able to take a smacking. He'll help essentially every part of your team play; his boost will help your team chase down any survivors, or help anyone smart enough to stay with you when things turn bad escape.

LANE PARTNERS

You should try laning with someone else who can harass them, especially a ranged dps.

Some strong choices are:
Gangplank- Gangplank's ability to harass and dish out early game burst damage with crits will really help with your lanal rape. Gangplank is a very strong carry, and he capitalizes on being fed very well. Synchronizing ults is very strong here.

Corki- Now, however unlikely it is that you'll find a Corki, let alone on your team, he is definitely a powerhouse combined with you in your lane. He's one of the strongest harassers in the game, and being that you both have godly farming, you'll be able to push very effectively. That is, if he's not in mid for some reason.

Caitlyn- Caitlyn's powerful early game damage and harassment will keep your lane sparkly clean. Caitlyn's ult will pick them off even in their turret.

Jax- Jax's early game burst damage will have your enemies hugging their turret for dear life. Your lane will also be very resistant to any mages.

Urgot- Urgot's borderline OP early game harassment is enough to make any lane hell for the other team, but combined with Galio's punishing nuke, and a suppress switch followed by a taunt is sure to get a few rage quits. Again, don't force him to be with you; he should be in a solo lane.

Here are some decent lane choices

Morgana- Morgana's snare and aoe make for a good combination with Galio. Synchronizing ults with these two is devastating in team fights.

Tryndamere- Tryndamere capitalizes very well on getting early game kills, and even if you're both melee you'll be able to disable and cut people down very quickly.

Twisted Fate- Twisted Fate is a very solid partner for Galio, having a sustainable form of harassment, and early game he can dish out some damage to capitalize on your ult, or chase them down with his Pick A Card.

PLAYING AGAINST:
Teemo- Harass his furry nuts off! Teemo's blind is of little to no concern to you, as you aren't a right click to win character.

Miss Fortune- Try and get a few levels in your Bulwark to get a heal from her Make it Rain. Don't stay in it too long, because the heal will turn into some damage. Better yet, avoid it all together- the slow is not worth the damage. But a strong Bulwark will help you withstand her punishing ult.

Zilean- I'm not saying max out your Bulwark, but definitely grab some early levels of it. It will definitely take some of the sting out of those bombs over your head. Galio is a decent counter to Zilean, just try and keep him at arm's length.

Twitch- Grab a piece of armor early to keep his damage at a minimum, and harass, harass, harass. Don't get caught in a situation where you're running from him, because that's just free damage for him.

Cassiopeia- I'm not sure if her DPS poison procs healing from your Bulwark, but if it did you should level it up to be a hard counter for her.

Galio- However unlikely it is, if you find yourself against another Galio, i can't imagine him getting a different two starting items. Chalice of Harmony into Mercury's Treads is the typical Galio start. So honestly, this is a tough match up, and it comes down to experience. Landing Resolute Smite is a very important deciding factor here;

Core Items

Thornmail Randuin's Omen Abyssal Mask
These items synergize well with your ult; they apply plenty of status effects when you're hit, and while they wish they couldn't hit you, they don't have a choice. They make your ult hurt, while still letting you take the hits like a champ.

Early game

I grab a Doran's ring to start out, because it gives you some AP and mana regen, so you can make your shots count and keep them coming too. The health it gives you gives you some good health.
Before grabbing your Mercury's Treads, get a Chalice of Harmony to help your mana regen. It helps you spam your [Resolute Smite/ Righteous Gust nuke combo without any guilt. It also gives you a nice bit of magic resist to help with defense and your casting power.

Once you get your Merc. Treads and your Chalice, get a Heart of gold first and start building your Randuin's Omen.

Mid Game

Things will start heating up; you should start ganking people and you'll often get your Randuin's with relative ease. Next comes your Thornmail, to keep any pesky carries off of you. But, if there's a marauding Veigar out there, you can go ahead and get your Force of Nature first. Try and catch people in your ult only in team fights; and always be there to support your teammates. You can always help in some way.

Late game

Building Abyssal Sceptor next is important to give you some more power in your happy nuking. The aura is also applied when you enemies get close, so it maximizes the effect of your ult. Don't just flap your way into a 5v1 and expect to kill them all with your ult; you're gonna die. Your ult hurts big with lots of people in it, but you can't kill all of them. Lich Bane Gives you and additional 270 attack or so after your nuke so you can dish out some big damage, and you get a nice bit of magic resist and AP, so you'll be plenty powerful. That's a much bigger nuke than your average Galio, so you will be an immensely durable damage dealer.

Optional Items

Banshee's Veil
Banshee's Veil: This item is definitely recommended for Galio. If you feel like that Lux/ Leblanc combo is still doing too much to slow you down, go ahead and grab one.

Quicksilver Sash
Quicksilver Sash: This item is great for the price, and it will definitely hold you over, but you should eventually sell it for a Banshee's Veil.

Guardian Angel
Guardian Angel: This is a great item for Galio, but I don't often find myself dead as Galio so I don't often get it. Nothing helps your team more than coming back from the dead and helping them out.

Spirit Visage
Spirit Visage: I used to get this item for Galio to make his heal more formidable, but eventually I did sell it for something better. Another nice mid-game item; a bit of health, and a boost to your magic resist. If you're solo laning, I strongly recommend getting this item.

Aegis of the Legion
Aegis of the Legion: Frankly an underrated item for tanks. If you want to go more support, this is a good item to help out your team. It gives a boost to all of Galio's qualities, so this item works well with Galio.



Here are some items that may seem like a good idea, but in the end are counter intuitive

Frozen Heart
Frozen Heart: The passive is nice, and the cooldown reduction makes it a tempting item, but I don't recommend getting this item because it drags down your ult, which capitalizes on getting as many hits as you can. It could be nice to fly through their team and slow them all down, but Randuin's does this along with a movement speed debuff.

Cloak and Dagger moonfair spwellblade Eleisa's Miracle"The Tenacity Items"- Cloak and Dagger, Moonfair Spellblade, and Eleisa's Miracle: The first one is unthinkable so I won't mention it, but the other two don't stack with Mercury's Treads, and if you're using different boots(For whatever reason) you're doing the job one item could do with two items. Eleisa's Miracle is the only one I would consider using, but I wouldn't even use it that long.
Zhonya's Hourglass
Zhonya's Hourglass: This item looks like it would be a good fit for Galio, but it just isn't for him. Drawing attention away from yourself as the tank is a little stupid; you need to get hit. And honestly I couldn't see the applications for this item on Galio.

My runes are fairly straightforward. Magic pen, armor, MR, health. Nothing fancy, and it's what you should shoot for.

I always take my Resolute Smite first; you'll land some good hits on them before they catch on and try and dodge it. It's also your slow, so you can help your teammate get first blood; not to mention it hurts a good deal. I level up my Resolute Smiteas a priority. But more often than not, my skill sequence is higgledy piggledy(that means all over the place), as I always adapt to the skill of those in my lane or who I'm facing.

Runic Skin


This is a very unique innate in that people have made whole builds based on this innate alone. It supplements your ability power from the start of the game, making him one of the few characters that starts the game with ability power.


Resolute Smite


Here's a very good ability: a slow with good AP ratios with great range that can drop minions like flies. It deals great damage all throughout the game, and it's a pretty big slow; a 40% slow is gonna make getting away really hard.

Bulwark

When you first look at this ability you may not see much. But think about it: Defense and offense in one ability, a heal, and a way to keep damage from that spamming Karthus at mid at a minimum. Casting it on yourself and running through minions is a good way to get some free hp, but you can cast it in yourself to take the thunder away from anyone trying to chase you down, or to give yourself a bit of an AP. This essentially buffs every aspect of Galio.


Righteous Gust

Galio's E is a nice speed boost that is yet another versatile spell with good AP ratios; it works like a ghost for anyone friendly in the resulting stream, it works as a getaway car for as many people as can fit in, and excells at harassing enemies in your lane. Use this and your Resolute Smite for some nasty farming.


Idol of Durand

And here is the crown jewel of Galio: a full team taunt, if placed right, that acts like a Thornmail and makes them focus the tank.
This is what this build really helps to bring out: good damage that can grab anyone in its radius, applying lots of status effects to turn around any teamfight, or you can plant yourself in the path of escaping allies and snag any enemies trying to chase your friends down, then just boost out of there.
The cooldown on this badboy hurts, so use it wisely.

Flash
Ahhh flash, my old friend. Whether it's escaping through jungle walls, setting up a nice /all ALAKAZAM, or countering their... well, flash, this spell has almost limitless uses for any character. An absolute must for Galio.

Clairvoyance
This spell is very useful, whether it's seeing who's in your lane or where their jungler is or if you're suspicious of a gank, this spell will tide you over nicely.

Here are some spells Galio could consider using:

Cleanse
You may have to switch around your masteries a little, but it should be well worth it for a tank.

Exhaust
Exhaust never hurt anyone. Essentially, you just made one of their enemies a wimp.

Fortify
Hey, Fortify with a taunt? Sweet!

Rally
I can think of some ingenious uses for this. Using it to tank a turret, for first blood, for team fights, it's underrated in my book, and would work well here.



And here's some bad ones:

Smite
Wrong smite xD

Heal
You're plenty durable Galio. You have a heal.

What is your nuke?
Why, it's
Try and nail the timing! There is some serious hidden damage to Galio, so let's calculate the damage on this.

AP= (242+90)/2=166+150
316 ability power!
80% of 316= 252 added damage to your two spells. 552( Resolute Smite ) + 492( Righteous Gust ) + 443( Lich Bane ) + 443( Lich Bane ) = 1930 damage before Magic resist and armor! So for an average carry that's about 1500 damage. You haven't even used your ult yet!

From the LoL wiki:

So there you have it. Playing Galio is a blast, and your team will thank you for that great save with your shield. Your match history is gonna be shining, and you'll silence all those haters. He may very well overtake Amumu as my favorite tank, as playing him is a unique experience. Plus, you get away with having a taunt in ranked ;)

Thanks for reading the build, so here's some rap for you:

Galio
Call him Palio
He's your friend
As their team he does rend
Asunder, and minds he does bend
As they lose control
While you simply lol
At faces you roll.
He's a lane bully
Beating you down
To your tower
With his power
Glaring back at you
With his level advantage
You sure do have a vantage
Point, from that death screen

5-20-11 Added Early Mid and Late game to Items

5-21-11 Changed summoner spells to include Clairvoyance

5-23-11 Added laning suggestions to Laning/Teamwork