In this paper, BiFe1-xMnxO3 (BFMO) nanoparticles with x = 0.0, 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30, were synthesized by a sol-gel method. Then, the structural, magnetic, dielectric and optical properties of BFMO nanoparticles were investigated. The structural properties of the samples were characterized by several techniques such as X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and X-ray diffraction spectroscopy (EDS). The magnetic, dielectric and optical properties of the prepared samples were also characterized by Vibrating sample magnetometer (VSM), LCR meter and UV-visible spectroscopy, respectively.