Terbium orthotantalate powders were produced with M-fergusonite type (I2/a) and M′-fergusonite type (P2/a) structures. The samples were studied by X-ray diffraction, Raman scattering, and photoluminescence measurements (emission and decay curves). The results showed that crystalline materials were obtained with all the 18 Raman-active modes predicted by group theory calculations. Also, it was observed through photoluminescence decay curves that the Tb 3+ ions occupies only one-symmetry site in both crystallographic arrangements. Photoluminescence emission curves exhibited some variation in spectral shape, peak position, and relative intensity as a consequence of their different crystalline arrangements. The dominated emission of Tb 3+ ( 5 D 4 → 7 F 5 ) is centered with a maximum intensity at 549.2nm (M-type) and 543.0nm (M′-type). Fluorescence lifetimes for M-TbTaO 4 and M′-TbTaO 4 were determined as 33.4μs and 1.25ms, respectively. M′-type materials seems to be the most suitable for luminescent devices and could be a potential green luminescent material due to the strongest emission if compared with the M-fergusonite type.