In the present work, a theoretical study has been performed targeting essential amino acids (EAA) Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine, and predicted their different physical and chemical properties by using computational techniques. Amino acids (AA), a fundamental structural unit of protein are amino and carboxyl-rich compounds having electrophilic and nucleophilic regions in it. The reactivity of AA were determined by computing molecular electrostatic potential (MEP) surfaces, counter plots, dipole moment, band gap, global reactivity parameters, and polarizability parameters. Spectral analysis (UV-Vis, Raman) helps in studying their electronic and vibrational properties. The polarizability and first order hyperpolarizability parameters were also computed to detect the nonlinear optical (NLO) behavior of AA. The comparison done with reference NLO materials Urea, Phenyl urea, and 3-nitroaniline showed that Phenylalanine have higher hyperpolarizability and can better to be used as a potent NLO material.