In the current work, a phytochemical analysis of the hydroethanolic extract of Leonotisnepetaefolia leaves was performed using the GC-MS analysis method. The extract was discovered to contain several phenolic chemicals. Plant extracts can be used to make metal nanoparticles, which is a quick, dependable, and inexpensive process when compared to other synthesis techniques. The biosynthesis, characterisation, and antibacterial activity of ZnONPs created from an extract of Leonotisnepetaefolia were examined in this study. Advanced instrumentation was used to analyze the shape, elemental composition, and other properties of nanoparticles. The average particle size was discovered to be 20 nm. The most visible damage is seen in scanning electron micrographs of the gram-negative bacteria Escherichia coli (E. coli) and the yeast Micrococcus luteus, which show damage to the cell walls. Between 320 and 335 nm, ZnO shows an impressive increase in absorbance in the UV-Vis spectrum. In the FTIR spectra, ZnO tensile vibrations at 426 cm-1 and 540 cm-1 were measured. The SEM investigation revealed that the particle size was between 30 and 40 nm. Particle size and particle load in zeta-size studies were 19 nm and -36 meV, respectively. Studies on the antibacterial activity of the produced nanoparticles revealed that they inhibited the growth of Escherichia coli (E. coli) and Micrococcus luteus. This study showed that ZnONPs may be made inexpensively and could be used as a carrier system for novel drug formulations in clinical therapy.