Negative active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

Disclosed are a negative active material for a rechargeable lithium battery that includes a core including silicon oxide represented by the following Chemical Formula 1; and a surface-treatment layer surrounding the core and including metal oxide represented by the following Chemical Formula 2; a method of preparing the negative active material; and a rechargeable lithium battery including the negative active material. The metal of the metal oxide is included in an amount of about 0.1 wt% to about 20 wt% based on the total weight of the negative active material for a rechargeable lithium battery. [Chemical Formula 1]SiOx [Chemical Formula 2]MyOz In the above Chemical Formulae 1 and 2, M, x, y, and z are the same as defined in the specification.