Infrared diffuse reflection spectra of O-H(ν O H ) and O-D(ν O D ) stretching vibration regions are used to characterize proton dissolution sites in high temperature proton conductors (HTPCs) of CaZrO 3 , SrZrO 3 and BaZrO 3 doped with trivalent Ga 3 + , In 3 + and Y 3 + ions. The number of observed ν O H band was three, five or six and two, respectively, for the CaZrO 3 -, SrZrO 3 - and BaZrO 3 -based samples. It was inferred that the two lowest bands below 2000 cm - 1 observed for SrZrO 3 -based samples were the ν O H bands for hydrogen bonding of O...H. Therefore, the number of proton dissolution sites was concluded to be three for the CaZrO 3 -based samples, three or four for the SrZrO 3 -based samples and two for the BaZrO 3 -based samples. The ν O H bands were observed at low wave numbers in the order of Sr(Zr,M I I I )O 3 - δ <Ca(Zr,M I I I )O 3 - δ <Ba(Zr,M I I I )O 3 - δ , i.e., hydrogen bonding strength of the dissolved protons is found to be in the order of Ba(Zr,M I I I )O 3 - δ <Ca(Zr,M I I I )O 3 - δ <Sr(Zr,M I I I )O 3 - δ . The average distances between two oxygen atoms, r O - O , in the original alkaline-earth zirconates are reported as r O - O (SrZrO 3 )<r O - O (CaZrO 3 )<r O - O (BaZrO 3 ). Strong hydrogen bonding was observed for the alkaline earth zirconate with short r O - O . It was concluded that the chemical environment of protons dissolved was primarily affected by crystal structure of the original zirconates.