Ultraviolet (UV) photodissociation dynamics of the SD radical in vibrationally ground and excited states (X ²Π_3/2, v″ = 0–5) are investigated in the photolysis wavelength region of 220 to 244 nm using the high-n Rydberg atom time-of-flight (HRTOF) technique. The UV photodissociation dynamics of SD (X ²Π_3/2) from v″ = 0–5 are similar to each other and to that of SH studied previously. The anisotropy parameter of the D-atom product is ∼−1; the spin–orbit branching fractions of the S(³P_J) products are essentially constant, with an average S(³P₂) : S(³P₁) : S(³P₀) = 0.51 : 0.37 : 0.12. The UV photolysis of SD is a direct dissociation from the repulsive ²Σ⁻ state following the perpendicular ²Σ⁻–X ²Π excitation. The S(³P_J) product fine-structure state distributions approach that in the sudden limit dissociation on the single repulsive ²Σ⁻ curve, but they are also affected by nonadiabatic couplings among the repulsive ⁴Σ⁻, ²Σ⁻, and ⁴Π states. A bond dissociation energy D₀(S–D) = 29 660 ± 25 cm⁻¹ is obtained.