Mn doped Si nanoparticles have been synthesized via a low-temperature solution route and characterized by X-ray powder diffraction, transmission electron microscopy, optical and emission spectroscopy, and by electron paramagnetic resonance (EPR). The particle diameter was 4 nm, and the surface was capped by octyl groups. Mn doping at 5% resulted in a green emission with a slightly lower quantum yield than undoped Si nanoparticles prepared by the same method. Mn2+ doped into the nanoparticle is confirmed by EPR hyperfine, and the charge carrier dynamics were probed by ultrafast transient absorption spectroscopy. Both techniques are consistent with Mn2+ on or close to the surface of the nanoparticle.