We show the visible and near-infra red (VIS-NIR) light spectroscopy of ZnO and Al:ZnO multi-layered thin film structures grown on oxidized silicon substrates. Using optical interference, the thickness of the multi-layered deposited ZnO and Al:ZnO can be determined. Using angle-based reflectance spectroscopy measurements and a method derived from reflectivity of dispersive, non-absorbing materials, the optical thickness of thin films samples are calculated. These calculations show an excellent agreement with the actual thickness of ZnO samples with a margin of error of <4% for a 20 layer (500 nm thick) film and <1% for a single-layer ZnO film. This work also investigates the anti-reflection properties of ZnO and Al:ZnO thin films at a variety of angles of incidence. Results show that film’s minimum reflectivity (< 8%) can be tuned in the visible frequency range, based on number of iterative layer depositions and subsequent thickness.