The aim of this study was to use the Single-Valued Neutrosophic Set (SVNS) to analyze 58 mutual funds, traded at the Istanbul Stock Exchange, under incomplete, indeterminate and inconsistent information. To this end, the performance of the funds was first evaluated using the most commonly preferred criteria like the Morningstar rating, Sharpe ratio, Treynor ratio, and Jensen ratio. Following these criteria, SVNS based entropy was used to rank the funds. The results of the entropy weights revealed Morningstar rating to be the most important evaluation criterion followed by Treynor, Sharpe and Jensen ratios respectively. Yapi Kredi Asset Management Foreign Technology Sector Equity Fund was found to be the most successful fund, while Is Asset Management BIST Technology Capped Index Share Fund (Equity Intensive) Fund was the least successful fund.