This　study　examines　the　tensile　behaviour　of　Ultra-High　Performance　Concrete　(UHPC)　specimens　reinforced　with　varying　steel　fibre　content　and　rebar　diameters.　An　experimental　campaign　involving　18　reinforced　UHPC　specimens　was　conducted,　following　individual　tensile　response　characterizations　of　UHPC　and　reinforcing　steel.　These　specimens　were　designed　and　fabricated　with　threaded　welded　steel　cages　to　transfer　loads　to　the　central　measurement　area.　Force-displacement　curves　were　measured　to　derive　stress-strain　curves　for　the　UHPC　component,　evaluating　the　impact　of　reinforcement　rebar　and　steel　fibre　content　on　UHPC＇s　mechanical　response.　The　analysis　revealed　that　steel　fibre　volume　content　significantly　influences　the　tensile　response　of　UHPC　reinforcement　more　than　the　steel　bar　diameter　and　yield　strength.　Comparing　the　strain　in　steel　bars　to　the　average　strain　in　reinforced　UHPC　specimens　indicated　that　post-cracking　deformation　concentrates　at　the　crack.　At　the　same　time,　the　bond　between　reinforcement　and　UHPC　remains　intact　in　uncracked　sections,　allowing　effective　load　transfer.　UHPC　specimens　reinforced　with　14　mm　diameter　steel　bars　displayed　a　significant　horizontal　segment　in　the　descending　phase　of　the　stress-strain　curve.　In　contrast,　specimens　with　18　mm　or　22　mm　diameter　bars　exhibit　a　progressive　stress　reduction　at　a　nearly　constant　rate.　Stress-strain　curves　of　UHPC　were　fitted　with　a　five-fold　piecewise　empirical　model　applicable　to　UHPC　with　a　reinforcement　ratio　higher　than　0.09%.　The　resulting　model　can　be　used　to　model　the　axial　behaviour　in　UHPC,　considering　the　effects　of　steel　reinforcement.