  In five dimensional models of Higgsless electroweak symmetry breaking, tree
level unitarity in gauge boson scattering is restored by the exchange of gauge
boson Kaluza-Klein modes instead of a Higgs boson. Unitarity of scattering
amplitudes involving top quarks requires also the Kaluza-Klein modes of the
third family quarks. It is shown that the relevant unitarity cancellations are
consistent with gauge symmetry breaking by boundary conditions. These results
are used to constrain the couplings of the top quark to Kaluza-Klein modes and
the implications for collider phenomenology are discussed.
