Abstract Crystallization behavior of rapidly solidified Ti–Ni–Sn alloys amorphous ribbons and martensitic transformation behavior after crystallization were examined by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Glass forming ability of Ti–Ni–Sn alloys increased with increasing Sn content and activation energy for crystallization increased from 151.2 ± 7.0 kJ/mol to 165.1 ± 9.0 kJ/mol with increasing Sn content from 5 at% to 7 at%, above which it almost kept constant. Crystallization occurs in the sequence of amorphous → (Ti,Sn) 2 Ni and B2 → B2 and Ti 3 Sn when Sn content is ≤5 at%, amorphous → (Ti,Sn) 2 Ni → B2 → B2 and Ti 3 Sn when Sn content is in the range of 5 at% and 10 at%, amorphous → (Ti,Sn) 2 Ni → Ti 3 Sn → B2 and Ti 3 Sn when Sn content is ≥10 at%. The crystallized Ti–Ni–Sn alloys showed the B2-R-B19′ martensitic transformation behavior. Rapid solidification was effective to separate the B2-R transformation from the R-B19′ transformation in Ti–Ni–Sn alloys.