  We find that in a multi-orbital system with intraorbital and interorbital
hopping integrals, the Hall conductance exhibits various topological quantum
phase transitions (QPTs) induced by on-site orbital polarization: integer
quantum Hall (IQH) plateau transitions, and topological Fermi liquid to IQH
transitions. Such topological QPTs are demonstrated in two systems: a $p$-band
spinless fermionic system realizable with ultracold atoms in optical lattice,
and a $d$-band spinful fermionic system closely related to giant orbital Hall
effects in transition metals and their compounds.
