Phosphorous doped ZnO (PZO) films were synthesized by RF magnetron sputtering using powder targets. Crystalline nature, morphology and chemical composition of the films were investigated by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). XRD showed hexagonal wurtzite structure with strong c-axis orientation for both doped and undoped films. FESEM study revealed uniform deposition of nanocrystalline thin films and XPS confirmed the P incorporation into ZnO lattice. The optical characterization showed that the average transmittance of PZO thin films is about 90% in visible region and optical band gap energy increased from 3.20 to 3.31 (eV) with the concentration of P doping. All thin films showed sharp absorption edge near the ̴ 370 nm. Photoluminescence (PL) properties showed significant changes in P-doped ZnO, providing evidence for existence several types of defects such as zinc interstitials (Zn_i), oxygen interstitials (O_i), zinc vacancy (VZ_n), oxygen vacancy (V_o) and oxygen anti-site defects (OZ_n) in the grown nanostructures.