This study aims to reveal how height/diameter ratio of column photobioreactors affect the growth and lipid content of microalgae. For this purpose, Chlorella variabilis cells were grown in aerated column photobioreactors with height/diameter ratio of 1, 2, and 3 in defined (BG11) culture medium. Results obtained showed that maximum microalgae biomass concentration, cell productivity, cell doubling time, and lipid productivity were found to increase as the height/diameter of photobioreactor increased. After 15 days of cultivation, the highest cell productivity (0.139 gdw/L.day), cell lipid content (21.1%) and lipid productivity (29.33 mg/L.day) were obtained in the photobioreactor with the highest height/diameter ratio (3), whereas the highest specific growth rate (0.045 h-1) was obtained in the photobioreactor with the smallest height/diameter ratio (1). These findings contribute to the knowledge on photobioreactor design and pave way for more efficient use of column type photobioreactors in producing microalgae.