The present disclosure relates to a method of manufacturing a quantum dot having a tunable and narrow light emission wavelength for achieving a high color purity, which for example includes preparing a mixture by dissolving an indium precursor and a zinc precursor in an acid, forming an In(Zn)P-based core by adding a phosphorus compound to the mixture, forming a first shell coated on the In(Zn)P-based core by adding a selenium compound and the zinc precursor to the mixture, and forming a second shell coated on the first shell by adding a sulfur compound and the zinc precursor to the mixture and in which the first shell is formed of ZnSe and the second shell is formed of ZnS.