This　paper　experimentally　investigates　the　seismic　behavior　of　tie　bar　stiffened　round-ended　concrete-filled　steel　tube　columns.　A　total　of　16　specimens　were　tested.　The　test　parameters　included　the　axial　load　ratio,　bending　axis,　tie　bar　ratio,　length　of　the　stiffened　region,　column　length-to-depth　ratio,　and　cross-sectional　shape.　The　seismic　performance　of　the　specimens　was　then　evaluated　using　four　indexes,　i.e.,　flexural　strength,　ductility,　stiffness,　and　energy　dissipation　capacity.　The　test　results　along　with　the　evaluation　confirmed　the　importance　of　using　the　stiffening　tie　bars　to　improve　the　seismic　performance　of　round-ended　concrete-filled　steel　tube　members.　©　2020　American　Society　of　Civil　Engineers.