First-principles calculation reveals that the hexagonal close-packed (HCP) Ti–H phases are energetically more favorable than corresponding body-centered cubic (BCC) and face-centered cubic (FCC) phases when 0 ≤ H/Ti < 0.26, while the FCC phases become relatively more stable when H/Ti ≥ 0.26. Calculation also shows that H concentration has different effects on mechanical properties of HCP, BCC, and FCC Ti–H phases, and at a certain H concentration,