The purpose of this study was to determine the optimal portfolio using Markowitz Model and Single Index Model. This type of research used in this research is descriptive research with quantitative approach. Samples taken as many as 21 shares of companies listed in the Jakarta Islamic Index (JII). The analysis showed that of the 21 samples contained 8 shares of companies that form the optimal portfolio based on the Markowitz model with the funding mix (AALI) of 2.88%, (ICBP) of 3.23%, (INDF) amounted to 30.93%, (LSIP ) 0.46%, (PGN) of 6.04%, (SMGR) amounted to 11.88%, (UNTR) amounted to 26.48%, (UNVR) amounted to 18.10%, which resulted in the expected return of the portfolio amounted to 0 , 01335 with a risk portfolio that is formed by 0.00105. Based on the Single Index Model there are nine (9) shares that form the optimal portfolio with the composition of the fund (UNTR) amounted to 17.15%, (UNVR) was 2.77%, (AALI) amounted to 10.85%, (KLBF) by 39, 11%, (ICBP) of 0.88%, (INDF) 15.95% (BSDE) amounted to 12.79%, (LSIP) of 0.14%, and (AKRA) 0.36% that generate return the expected amounting to 0.01878 to 0.00097of portfolio risk.