Gerald Tsai Jr. (; March 10, 1929 - July 9, 2008) was an investor and philanthropist who helped build Fidelity Investments into a mutual fund powerhouse.

After starting Fidelity Investments' first publicly sold aggressive growth fund in 1958, the Fidelity Capital Fund, he later founded the Manhattan Fund, an aggressive growth fund, in 1965. Tsai sold his interest in the fund complex in 1968 but continued to manage the funds. By 1969 the