Fox vs. Samus Super Smash Bros. 4 tiers, match-up votes and discussion

Down B

Many Samus mains like ESAM and IcyMist put this matchup as one of if not Samus's worst matchups. Here's my explanation:
The neutral is in Fox's favor. Reflector, as purplepenguin mentioned, forces Samus to reserve her Missiles and thus stick with Grapple Beam (zair). Lasers are the next step: they force Samus to either eat them while she throws out zair, or try to rush Fox down, which goes against her play style. Either way, Samus has to approach, which given her worse ground mobility is hard to do against Fox (despite being faster in the air). The biggest problem Samus has in this matchup, however, is that Fox juggles her for hours with his up air, just like Pikachu does. If he lands an up air, he can do it in rapid succession since Samus's counter options are either too predictable or too slow. If he misses, Fox can fastfall, up tilt Samus, then restart the juggle. This forces Samus more to the ledge, and since she isn't edge guarding, she will overall be in disadvantage for a longer time compared to when she wins the neutral against Fox. Even with her missiles to block Fox's recovery and Charge Shot, Fox can back air her from a ledge trump, so she needs to watch where he is at all times. About the best thing I can say Samus has in this matchup is the mind games she can get on Fox: when she has Charge Shot online (which against Fox is a chore), she can bait him to shine, then zair or otherwise approach, or even shoot Charge Shot at him if he is close enough and thus punish. Samus's combo game, however, is better against heavyweights than fastfallers, as Fox's fast falling speed and high gravity make it harder for her to juggle him. Unlike Fox, who has the aforementioned ledge trump to back air and various things into up smash, Samus can't actually KO Fox outright from her usual combos except if the Fox has bad S/DI or there are a bunch of platforms (a double edged sword in that case). Bottom line: if you main Samus, you will want to switch to ZSS against Fox. There's plenty more that she can do to him.