The spectroscopic properties and tunable laser performances of the orthorhombic perovskite Tm:GdScO3 crystal grown by the Czochralski method are comparatively studied for polarization along different crystallographic axes. The polarized emission spectrum of Tm:GdScO3 along the b-axis exhibits, to the best of our knowledge, the broadest bandwidth among all the single Tm3+-doped bulk gain media, indicating the strong inhomogeneous line broadening of Tm3+ ions in GdScO3 and thus leads to a broad and smooth gain spectrum. Tunable laser operation with a tuning range as broad as 321 nm from 1824 nm to 2145 nm is achieved, which indicates its potential for few-optical-cycle pulse generation in the 2-µm spectral range.