In this study, a pulsed Nd:YAG laser welding method is implemented to join Ti-G2 (1 mm thick) to AA3105-O (0.5 mm thick) via a ring of spots filled with AlScZr alloy (0.15 mm thick). The filler material improved the weld’s microstructure and mechanical properties by reducing the undesirable intermetallic compounds (IMCs) such as TiAl₂ and TiAl₃ in the aluminium re-solidified zone near the titanium/aluminium interface. The joints having AlScZr filler were mostly failed at Al heat affected zone (HAZ) during the tensile shear test. The addition of zirconium to binary Al–Sc system formed a substitutional solid-solution in which 50 wt% Zr+10 wt% Ti replaced Al₃(Sc,Zr,Ti). Scandium had a strengthening effect by solid-solution and precipitation hardening effect due to the formation of Al₃(Sc,Zr) particles. The joint strength rose from 86% (of the base Al strip) for autogenously laser weld to 102% with filler metal. Hardness increased steadily at the Ti/Al interaction zone, and the maximum hardness was reduced from 650 HV to 570 HV when filler metal was utilized.