  We propose a tri-hypercharge (TH) embedding of the Standard Model (SM) in
which a separate gauged weak hypercharge is associated with each fermion
family. In this way, every quark and lepton multiplet carries unique gauge
quantum numbers under the extended gauge group, providing the starting point
for a theory of flavour. If the Higgs doublets only carry third family
hypercharge, then only third family renormalisable Yukawa couplings are
allowed. However, non-renormalisable Yukawa couplings may be induced by the
high scale Higgs fields (hyperons) which break the three hypercharges down to
the SM hypercharge, providing an explanation for fermion mass hierarchies and
the smallness of CKM quark mixing. Following a similar methodology, we study
the origin of neutrino masses and mixing in this model. Due to the TH gauge
symmetry, the implementation of a seesaw mechanism naturally leads to a low
scale seesaw, where the right-handed neutrinos in the model may be as light as
the TeV scale. We present simple examples of hyperon fields which can reproduce
all quark and lepton (including neutrino) masses and mixing. After a
preliminary phenomenological study, we conclude that one of the massive $Z'$
bosons can be as light as a few TeV, with implications for flavour-violating
observables, LHC physics and electroweak precision observables.
