Vector-like quarks are predicted in various extensions of the Standard Model and their existence is now being probed at the LHC. In this talk I will present an overview of current bounds on the masses of vector-like quarks belonging to different SU(2) representations, and in the following I will focus on the phenomenology at the LHC of a non-standard doublet with hypercharge 7/6, which contains a top partner t' and an exotic quark with charge 5/3.