A facile template assisted sol-gel method has been used to prepare nanoparticles of tetragonal zirconia (t-ZrO2) with spherical morphology and porous structure along with mono dispersibility. The medium assisting growth of nanoparticles mainly consisted of ZrOCl2 center dot 8H(2)O and NH4OH as reactants in a 1: 2 mixture of Isopropyl alcohol (IPA)-polyvinyl alcohol (PVA) as the dispersing agent. The effect of medium, IPA-PVA mixture on crystallite size and agglomeration was studied and discussed on the basis of XRD and also based on possible surface reactions. More over reacting medium and calcination temperature has vital role in determining the crystallinity and morphology of ZrO2. Trials based on mode of addition of the reacting medium followed by calcination provides mesoporous, spheroid, monoclinic zirconia (m-ZrO2) with an average particle size of 15 nm. The sample prepared under optimized conditions (2 wt% PVA-IPA) showed pure tetragonal crystallite phase with an average particle size of 5 nm, surface area of 56 m(2) g(-1), and a mesoporous structure after calcination at 600 degrees C for 5 h. The tetragonal (t-ZrO2) phase formed were stable and showed spherical morphology up to 600 degrees C after which the nanostructure was disturbed drastically; the agglomeration leads to structure collapse forming hard conglomerates and finally leads to monoclinic crystalline phase. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.