Brillouin amplification and lasing are demonstrated in a single-mode ${\mathrm{As}}_2{\mathrm{Se}}_3$ chalcogenide fiber. A Brillouin gain of $42\mathrm{dB}$ was measured in a $4.9\mathrm{m}$ long fiber for a pump power of $68\mathrm{mW}$ at a $1.56\mathrm{\mu }\mathrm{m}$ wavelength. In addition, a compact ${\mathrm{As}}_2{\mathrm{Se}}_3$ fiber-based Brillouin laser with a threshold power of $35\mathrm{mW}$ and a slope efficiency of 38% for nonresonant pumping is demonstrated.