The Manganese Dioxide nanoparticles (MnO2 NPs) were synthesised using chemical method, turmeric extract and Lemon extract leaf extracts by green synthesis method. The synthesised nanoparticles were characterized by XRD, FESEM techniques and UV-Vis absorption. XRD analysis confirms that the prepared MnO2 NPs was in orthohombic structure, and the size of MnO2 NPs was estimated in the range of 89.388, 65.947 and 65.924nm for chemical method, turmeric extract and Lemon extract leaf respectively. FESEM images revealed that the particles were spherical in shape. The absorption of all oxides decreases with increasing wavelength for all samples prepared by both the chemical and green methods. Synthesized MnO2 nanoparticles were found to exhibit good antibacterial activity, with MnO2Nps extracted from lemon showing higher antibacterial activity with zone exceeding 20 and 25 mm for Gram-negative bacteria (E. coli and Klebsiella sp.) and 26 and 19 mm for Gram-positive bacteria (S. aureus and S. epidermidis), respectively. than those extracted from turmeric with zone exceeding 15 and 13 mm for Gram-negative bacteria (E. coli and Klebsiella sp.) and 13 and 14 mm for Gram-positive bacteria (S. aureus and S. epidermidis), respectively. and 13 and 13 mm for Gram-negative bacteria (E. coli and Klebsiella sp.) and 10 and 5 mm for Gram-positive bacteria (S. aureus and S. epidermidis), respectively chemically synthesized.