Nanoparticles are one of the most widely studied materials in this century, and they have important uses in various fields, including agriculture. Bio-stimulants play a vital role in the sustainable development of horticultural crops. The aim of this study was to assess the effect of nano zinc and bio-stimulants (salicylic acid, moringa extract, seaweed extract) on growth, yield, and quality of roselle plants. The experiment was conducted during 2018 and 2019 and was a completely randomized split-plot design. Nano zinc oxide of 0, 5, 10, and 15 ppm was used as the main plot, and bio-stimulants were used as the sub-plot. The results showed that application of nano zinc led to significant increases in growth, yield, photosynthetic pigments, as well as anthocyanin content associated with increased zinc content in leaves. The highest values ​​of all traits ​​occurred under treatment of 10 ppm of nano zinc. Also, bio …