The synchrotron x-ray absorption near edge structures (XANES) technique was used in conjunction with first-principles calculations to characterize Al-doped ZnO films. Standard characterizations revealed that the amount of carrier concentration and mobility depend on the growth conditions, i.e. H_{2} (or O_{2})/Ar gas ratio and Al concentration. First-principles calculations showed that Al energetically prefers to substitute on the Zn site, forming a donor Al_{Zn}, over being an interstitial (Al_{i}). The measured Al K-edge XANES spectra are in good agreement with the simulated spectra of Al_{Zn}, indicating that the majority of Al atoms are substituting for Zn. The reduction in carrier concentration or mobility in some samples can be attributed to the Al_{Zn}-V_{Zn} and 2Al_{Zn}-V_{Zn} complex formations that have similar XANES features. In addition, XANES of some samples showed additional features that are the indication of some α-Al_{2}O_{3} or nAl_{Zn}-O_{i} formation, explaining their poorer conductivity.