Single crystals of binary Ti 3Al and ternary Ti 3Al-V alloys with the D0 19 structure were deformed in compression at 20–900°C. Slip systems of the {10 10}〈1 210〉- type and the {11 21}〈 1126〉- type were observed in these alloys throughout the entire temperature range depending on orientation, but the {11 21}〈 1126〉- slip was limited to orientations near [0001]. the basal (0001)〈1 210〉- slip activated in quenched Ti 3Al. The CRSS for the {10 10}〈1 210〉- slip in the binary and ternary alloys decreases monotonically with increasing temperature. In the ternary alloy the CRSS for the {10 10}〈1 210〉- slip shows a violation of Schmid's law, while the binary alloy obeys the CRSS law. When Ti 3Al is deformed by {11 21}〈 1126〉- slip the CRSS for the slip exhibits an anomalous peak in the temperature-CRSS curve but the addition of vanadium suppresses the extent of the anomalous strengthening.