In this study, hydrogen production from water splitting in N-2 using an atmospheric pressure rotating gliding arc plasma was investigated. The effect of input H2O concentration and total flow rate on the performance of the plasma water splitting process (e.g., H-2 and O-2 yield, H-2 production rate, and energy yield of H-2) was investigated. N-2 showed a pronouncedly facilitating effect on the H2O splitting and H-2 production process due to the reactions of the excited N-2 species [e.g., electronically excited metastable N-2(A)] with the H2O molecules. The maximum H-2 production rate reached up to 41.3 mu mols(-1), which is much higher than that of other typical non-thermal plasmas (e.g., similar to 0.2 mu mols(-1) for a dielectric barrier discharge). Optical emission diagnostics has shown that in addition to the NO, N-2, and N-2 (+) that were observed in the pure N-2 spectra, strong OH and NH emission lines also appeared in the H2O/N-2 spectra. OH radical is considered as a key intermediate species that could contribute to the formation of H-2, O-2, and H2O2. The increase of the H2O concentration could lead to a continuous enhancement of the OH intensity. The rotational temperature of N-2 (+) dropped drastically from 2875 +/- 125 to 1725 +/- 25 K with the addition of 1 % (mol/mol) H2O into the N-2 plasma.