We study the constraints on t → u flavor changing neutral Higgs coupling and how it may be explored further at the LHC. In the general two Higgs doublet model, such transitions can be induced by a nonzero ρ tu Yukawa coupling. We show that such couplings can be constrained by existing searches at the LHC for m H , m A , and m H þ in the sub-TeV range, where H, A, and H þ are the exotic CP-even, CP-odd, and charged scalars. We find that a dedicated ug → tH=tA → ttū search can probe the available parameter space of ρ tu down to a few percent level for 200 GeV ≲ m H , m A ≲ 600 GeV, with discovery possible at high luminosity. Effects of how other extra top Yukawa couplings, such as ρ tc and ρ tt , dilute the sensitivity of the ρ tu probe are discussed.

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