Titanium aluminide alloys based on the γ-TiAl intermetallic compound are emerging as potential materials for high performance applications on aircraft engines components, aerospace vehicles and automotive engines, owing to their low density, high specific stiffness, excellent strength retention at high temperature and good creep and oxidation resistance. The development of adequate techniques to join γ-TiAl alloys, either to themselves or to other materials, is a key issue regarding the effective use of these alloys. Understanding of the reaction mechanisms that promote bonding is mandatory when optimization of the joining procedure is envisaged.