Multicomponent TeO2-Bi2O3-ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. We observed that thin films sputtered in an oxygen-rich environment are optically transparent while those sputtered in an oxygen-deficient environment exhibit broadband absorption. The structural origin of the optical property variation was studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy which revealed that the presence of under-coordinated Te leads to the observed optical absorption in oxygen-deficient films.