This study investigates the sensitivity of mutual fund flows to the different types of mutual fund fees, including management fees, front-end load fees, along with back-end load fees and compares the relative level of sophistication among investors in bank related funds versus non-bank related funds and also tax benefit funds versus non-tax benefit funds. Furthermore, this study examines the relationship between change in fund fees and fund flows. The data are from Thai equity funds during the period from 2006 to 2019. Based on the analysis, we found the evidence that there is difference of sensitivity of fund flows to management fees among investors in bank related and non-bank related funds; on the contrary, there is no different among investors in tax benefit and non-tax benefit funds. The negative relation between management fees and fund flows appears to be for investors who invest in bank related funds, both of tax benefit and non-tax benefit. On the other hand, the positive relation between management fees and fund flows is in investors who invest in non-bank related funds, both of tax benefit and non-tax benefit. This implies that investors in bank-related fund, they are more concerned about ongoing expenses, while advertising activities are more attractive in non-bank related funds. However, there are no relation between both front-end and back-end load fees to fund flows, although the overall picture of the Thai mutual fund, there is negative relation between front-end load fees and fund flows which the result was dominated by the attractiveness of bank-related funds that also have lower front-end load fees compared to non-bank related funds. Moreover, this study found that investors pay attention to changes of front-end fees, although it is considered as one-time costs, while, they pay less attention to changes of management fees and back-end fees which are less salient.