Galio vs Katarina Mid Matchup
Galio Mid wins 52.8% of 2,729 Low Elo games against Katarina Mid, +2.3 points vs expected, 2-patch window 26.19-26.20.
Researched on LoL patch 26.20. Tips are written to hold at any rank; stats come from Low Elo ranked games up to patch 26.20.
Why Galio is favored
Galio's taunt and knockup can interrupt Death Lotus(R), while his magic shield and durable build let him survive Katarina's burst. Katarina has to bait those control spells before she commits to her channel.
Measured in High Elo: Galio wins 3.0pp more often than expected over 1,359 games.
How to play as Galio
Keep W or E ready for Katarina's R or dagger entry; your crowd control can stop her channel and leave her vulnerable to a counterattack.
Shield of Durand(W) taunts nearby enemies and Justice Punch(E) knocks up the first champion hit, either of which can interrupt Katarina's Death Lotus(R).
Colossal Smash(P) and his magic shield give Galio tools to trade back into Katarina's magic burst.
How to play as Katarina
Bait Galio's W and E before channeling R; take short trades around his cooldowns instead of diving into both control spells.
Sources
These notes come from r/galiomains, checked against the champions' abilities.