The last few decades have witnessed humongous increase in usage of nanotechnology-based products at global level. However, this attribute comes with a jeopardy in the form of heightened risk of discharge of the nanoparticles into the environment, including the aquatic water bodies. Nanomaterials are more potent for industrial as well as commercial usage owing to their exceptional properties such as small size and higher surface area to volume ratio. However, this very attribute of the nanoparticles makes them hazardous in comparison to the bulk material and raises concerns about their usage in the industrial sector and accidental release into the environment. However, concentrations of nanoparticles determine the level of toxicity. Nanoparticles also have shown positive effects on algae at a certain concentration. In this context, the current review article aims to analyse the ecological aspects of exposure of zinc oxide nanoparticles onto algal population present in the water bodies. Algae form the primary producers and the connecting link across various food webs, owing to which, even a slight alteration in the algal population may trigger an upheaval in the entire aquatic ecosystem. The present review provides a succinct overview of the studies showing effects of zinc oxide nanoparticles on the algal growth and metabolism and on photosynthetic efficiency of algae by exposure to zinc oxide nanoparticles.