Purpose The purpose of this paper is to determine the effects of environmental factors in open-plan offices with the same characteristics but with different workstation partition heights (1.10, 1.40 and 1.65 m) on perceptual evaluations of office employees. Design/methodology/approach In this research, the effects of environmental factors on employees' perceptual evaluations in open-plan offices at the Golbasi Region of Ankara were measured with a detailed questionnaire. The research data were obtained from 81 employees who agreed to fill out the questionnaire and who use open-plan offices. Findings It was found that the office environments with 1.65 m workstation partition heights were more favorably assessed for each of the items of planning and of privacy that form the dependent variables compared to the office environments with 1.10 and 1.40 m partition heights. On the other hand, the office environments with the 1.10 and 1.40 m partition heights were more favorable for lighting items than the 1.65 m partition height office environments. In addition, young employees had a more positive tendency toward the perceptions of environmental factors, including different workstation partition heights in open-plan offices, compared to older employees. Originality/value The significant contribution of this research is that it provides valid data and makes a valuable contribution to the body of knowledge in open-plan office design.