IMPORTANT!
Head immediately to the "Countering Caitlyn: General Tips" chapter if you are looking for a really quick rundown of how to counter this champion - perfect for just before a match or a tournament! Otherwise, read up on the entire guide for an in-depth look.

Hello. As many members of MOBAFire know, Caitlyn is a highly viable marksman with very strong poke, the longest autoattack range of any marksman, and decent map control. She is one of the most played marksmen of Season 3, and many seem to do poorly against her based on her overwhelming list of champions she can perform well against in lane. Most frustrating is both her trap ability, making bushes a dangerous place to be unwarded, even more so than normal, and her ultimate, which almost always secures a fleeing kill well out of the way of any of Caitlyn's allies' reach.

Hopefully, through using this guide, you can understand the mechanics of Caitlyn, as well as come to terms with her strengths and weaknesses, and, just maybe, even become knowledgeable enough to successfully win a lane against her with someone she supposedly counters.

Enjoy!

~Timothy_Depp

Before going into the full swing of defeating Caitlyn, we must first understand this champion. The first and most notable characteristic of the Sheriff of Piltover is that she is a marksman, (the new-fangled term for an AD carry) however, this is her only attribute, as some can also be mages or fighters. This is important to note, as her ability composition dictates this attribute; her moves are designed for poking, and, as a result, weakening her target so she can secure kills against them.

With this in mind, let's take a look at her moves. Remember - these are designed for weakening her targets.

(Innate)

Essentially, this is Caitlyn's best early game ability. Her range, the highest in the game, allows her to harass madly, and it allows her a much better farm rate since it saves her from messing up key last hits. Additionally, a Caitlyn premade with a support who stands with her in her hedgerow, warding both sides to stay safe, allows her to poke ever more due to the double stack when firing from a bush.

(Q)

An even more potent poke than her innate ability, the Piltover Peacemaker is a dangerous ability to dodge, as it ignores creep and travels its entire firing path to deal damage. Thankfully, it has marginally less reach than her autoattack, meaning an alert marksman can avoid this painful ability. This ability allows Caitlyn a decent farming mechanic against a weakened wave, so beware if she uses it to push down a lane.

(W)

These traps are irritating and extremely inconvenient to land on, and they are invisible when placed in a bush. Caitlyn users like to place one or two in a lane to snag careless opponents, but even more of them place trap inside of bushes, typically at the very edge, to catch sneaky gankers or junglers attempting a brush gank. A smart Caitlyn will also places traps at the feet of a target standing its ground against her, or in the path of a close-by but retreating target.

(E)

The escape mechanic of Caitlyn, this lifesaver not only spaces out Caitlyn from her opposition, but also deals magic damage and slows them as well. Thankfully, this move deals magic damage, meaning it cannot be built successfully as an addition into her DPS arsenal. If Caitlyn is liable to use this move effectively any time a gank is in progress, it would be best to instead focus the support.

(Ultimate)

A very long-range ultimate, this move is capable of killing virtually anyone low enough and close enough to be in her sights. The bad news is, even if you utilize Ghost or Flash to space yourself out after she activates it, you still will be in range, as the mechanic of her ultimate deems any locked-in target never to be out of range once it fires. The only way to escape death is to use Barrier, be healed or to life steal some health back, or most simply, have someone take the shot in time to save you.

Playing Caitlyn on her free week or owning her will allow you to firsthand experience her play style, which is a good thing to have under your belt when the time comes to face her. By having knowledge of what she is likely to do in a fight and how she will engage your team, you can better set yourself up to win against her. As always, though, expect the unexpected, as everyone plays a champion differently.

Since Caitlyn passively gains a beefed-up autoattack the more often she does it, it is understandable and expected to see her build up lots of critical strike chance and attack speed, as these synergize well with this innate. Raw attack damage may also be built to allow her Q and ultimate more damage on-hit. Items typically seen on any Caitlyn build include Blade of the Ruined King, Infinity Edge, Phantom Dancer and Last Whisper.

Considering this, Vayne builds sometimes match Caitlyn builds, as both have a stacking autoattack passive as part of their DPS capacity; however, endgame results between the two builds tend to vary, as their overall needs evolve as they level.

A Caitlyn who has been considerably feed tends to rush a large sum of damage and criticals, with only a small sum of attack speed, since their resulting build will allow high ultimate damage, and therefore easier kill secures. An underfed Caitlyn may rush BotRK and Infinity Edge quickly, to allow their innate ability higher on-hit damage and a better survival chance in a one-on-one battle.

Very rarely, on-hit effect items such as the Black Cleaver and Frozen Mallet may be built, as an on-hit effect combined with the AS from BotRK (as well as its own on-hit effect) and/or Phantom Dancer can mean constantly stacked debuffs resulting in a much weaker target to kill. Another on-hit item that was once very popular on Caitlyn was Runaan's Hurricane. Though now seen as obsolete, it should be noted that it still grants Caitlyn a much faster stacking of her innate ability, meaning it can still be very potent on a well-played Caitlyn.

Realize that the basis of the Caitlyn build encompasses on-hit damage, either from citicals or on-hit items, and lots of attack speed to compliment both her innate ability stacks and said on-hit damage.

Now for counter items... Ninja Tabi are a simple choice for any fed ADPSer, as it adds armor and reduces damage from basic attacks; Caitlyn is definitely all autoattacks, so these are a great boot set for tanks or desperate marksmen. Frozen Heart adds a massive armor stat, as well as mana and CDR, though its best strength against Caitlyn is its attack speed reduction, rendering her passive more a tickle than a stickery poke; best of all, supports such as Taric and Thresh go greatly with this, and either of team should go for it if no allied tank has it yet. Thornmail is pretty simple to understand; every time she autoattacks or deals physical damage to you, she gets some magic damage dealt in return, although this will outright stop her from focusing you. Randuin's Omen is a nasty surprise, as it makes you considerably tanky versus her, although the passive is where it shines; dropping this attack speed and movement speed slow onto her forces her to retreat, meaning you can instantly turn on her with this item. The last one is not cheap, though it is the most accessible of all of these items to a marksman - Mercurial Scimitar. By offering a "get-out-of-jail-free" card for you to pull when her traps snare you, you can avoid a sealed fate against her ultimate or when you get caught by one in sketchy unwarded territory. The damage and MR are also nice bits to have on any marksman.

Now that we've gotten through how she plays, let's start to focusing on taking the fight to Caitlyn. Take notes no longer and simply read on how to beat the poking queen!

Fighting Caitlyn with the advantage of recognizing that she will be the enemy marksman is a great hold to have over the enemy team, but knowing that she will be competing is not worth knowing if you know not whom to pick against her. Picking out weak and strong picks versus her is just one of many ways of gaining an advantage, so I will not only explain the top 4 weakest and strongest combatants against Caitlyn, but I shall also offer insight as to why these champions stand the way they do against her.

The following picks come from ChampionSelect.net, CounterofLegends.com, LoLCounterPicks.com and my own personal experience.

Caitlyn - Strong Against

1. Corki: Corki has a painfully short autoattack range, and this forces him to farm uncomfortably close to Caitlyn, meaning she can relentlessly poke him the entire laning phase. Although he can burst powerfully in a fight against her and put her on the run, Caitlyn can also poke him down before he can complete this burst leaving him vulnerable to the support or her ultimate. Corki also cannot avoid Caitlyn's traps with his W, Valkyrie, further placing him at disadvantage to her.
2. Vayne: Vayne's markedly weak early game places Caitlyn at substantial advantage over her. Vayne must be extremely careful when farming, as, like Corki, her autoattack range is not too great, and her abilities would not offer much hope to her fight if Caitlyn was free to poke her down in the process of engagement. Later into the game, Vayne can pile-drive Caitlyn, but only if she was able to farm against her at all during the laning phase.
3. Graves: Graves offers good damage output against Caitlyn, but, like many of the picks here, their autoattack range is not enough to place them at kill distance to Caitlyn, meaning she is free to poke Graves as much as the above two. Graves' poke is good against Caitlyn, but his farming is fragile, and, with pusher such as Caitlyn, this can mean difficult times for obtaining gold. Graves' aggressive play style is restricted as he is forced to play safe and almost exclusively farm against Caitlyn.
4. Twitch: Twitch has strong burst as well, although Caitlyn can trap Twitch and leave him vulnerable to counterattack. Her traps cause her target to be seen, even when stealthed, meaning Twitch cannot surprise attack Caitlyn, especially if she places them along the wall bushes, a favorite angle of attack for Twitch users. Additionally, even if Twicth begins stealthing away after being sighted in by Caitlyn's ultimate, it always gets the kill if Twitch was close enough once she scoped him in.

Caitlyn - Weak Against

1. Sivir: Sivir is hands-down the best Caitlyn counter in the game, as virtually every move that Caitlyn uses is an on-hit ability, any of such abilities Sivir's Spell Shield can block. In laning phase, Sivir's Q, which is painful no matter what level it is used, offers significant return poke against Caitlyn, offering retaliation most marksmen cannot engage in. The largest advantage when it comes to laning is that Sivir's Spell Shield, which blocks Caitlyn's ultimate no matter how low Sivir was, is also a sustaining tool; Caitlyn's traps can feed mana back to Sivir as per her E's passive, meaning Sivir gets free mana to poke with all laning phase.
2. Kog'Maw: Kog'Maw is the only marksman than can consistently outrange Caitlyn, as his Caustic Spittle permits when activated. His ultimate, a mortar-like on-hit ability, can shell Caitlyn relentlessly as she attempts to go in for a poke or retreat to regain her health. Overall, however, Kog'Maw has better farm and poke, as well as substantial kite with both his ultimate and his Void Ooze.
3. Varus: As with many marksmen who use poke to bully their opponents to keep them underfed, Caitlyn suffers terribly in-lane against Varus, who is designed to throw poke right back at an aggressive laner. His healing reduction and long-range poke severely cripple Caitlyn if she attempts to close in for a fight, and Varus' passive Blight stacks much faster and promotes more damage than Caitlyn's innate ability, granting Varus free-range to farm and sustain during laning phase.
4. Taric: Although not a marksman, anyone who knows that Caitlyn is going to be the enemy marksman should know that Taric is arguably the best support against Caitlyn, no matter whom he is supporting. Taric is a tank support, which Caitlyn tends to have trouble keeping down in a bottom fight; he can take her shots during a battle and keep the team's marksman safe as s/he works down Caitlyn. All of his abilities work against Caitlyn greatly: his Q heals both he and his target, his W passively grants armor to allied champions, nullifying Caitlyn's poking, his E is a long-range stun that can mean death for a weakened Caitlyn, and his ultimate is a serious damage steroid that can win nearly any fight for his marksman.

Note that even with or without counters or being countered, the concept is just a suggestion to level the playing field, and that a counter from either side is never a won or lost game. Do realize, however, simply by knowing weak and strong picks, you can better synergize your team against Caitlyn, should she do well in the laning phase.

These 15 tips are suggestions you could get from anyone experienced in beating Caitlyn in-lane, as I have picked up many along the way, as well as come up with a few myself. Some are pretty nondescript, but others are for serious counters in shutting her down, should she become unbelievably fed. Read through them all to understand beating her and what to do should any situation arise.

1. Caitlyn is built around poking and bullying, therefore outfarming her opponent in the process or gaining kills if her target is careless. By outsustaining her poke in any way you can, be it potions, life steal or another tactic, you will do considerably better in-lane.
2. Caitlyn is quite squishy early game, and remains frail into late game; play aggressively to starve her of gold and keep her as weak as a toothpick.
3. Hard CC is a death sentence to Caitlyn if you know you can kill her; have your support or jungler land some to gain an immediate advantage.
4. Knowing when and where Caitlyn lays traps can add considerable ease to your jungler's ability to gank bottom lane.
5. Exhaust should be equipped by either bottom laner to drive down Caitlyn's ability to land a kill or fight back.
6. Mercurial Scimitar, though not necessarily cost-effective if bought early on, is well-worth the investment if Caitlyn's traps are your greatest issue.
7. Barrier is an excellent spell against Caitlyn, as it can save your life from her ultimate if no one is capable of blocking it.
8. Tanks and tank supports should always buy Frozen heart whenever feasible, as it greatly weakens Caitlyn's DPSing style.
9. Tanks suffering from Caitlyn's immense poke during the period before a team fight will find great sanctity in purchasing Randuin's Omen or Thornmail.
10. Caitlyn has 3 abilities that are directly avoidable; stay alert to avoid her added damage potential from her traps and Q.
11. Staying by a trusting ally with Flash is recommended if you are prone to going low in a team fight; when Caitlyn attempts to use her ultimate on you, said ally can Flash into the path of the shot and save you.
12. Bursty champions are excellent against Caitlyn, especially assassins.
13. Mages should focus Caitlyn, as her naturally low magic resistance opens her up to being melted by a well-fed mage.
14. Tanks with Randuin's should immediately run, blink or dash to Caitlyn during a team fight and activate its passive to render her useless for a few seconds.
15. Unless Caitlyn obtains a Blade of the Ruined King, increasing your maximum health can prove effective against her poke.

I appreciate any feedback, and I shall change everything that is felt as needing maintenance.

Changelog
2/8/13: created as bare-text format