<p>The effect of titanium (Ti) addition, substituting manganese (Mn), on the martensitic transformation (MT) of Ni₅₀Mn_37-xIn₁₃Ti_x alloys, where x = 0, 1, 2, 3, and 4 at.%, was investigated. Ti was introduced to reduce the brittleness of the Ni₅₀Mn₃₇In₁₃ alloy and adjust its transformation temperatures. Differential scanning calorimetry revealed that increasing Ti content progressively reduces the MT temperatures, reaching values below room temperature (RT) at 4 at.% Ti, while the thermal hysteresis remains nearly unchanged. X-ray diffraction confirmed a structural change from martensite to austenite at RT with higher Ti substitution, consistent with the calorimetric results. Microstructural analysis showed that Ti promotes grain refinement and the precipitation of a secondary phase. Vickers microhardness measurements indicated a slight increase with Ti content. These findings highlight the role of Ti in tuning the MT temperature range and modifying the microstructural features of Ni–Mn–In-based Heusler alloys.</p> Graphical Abstract <p></p>