Sethi, who is leaving to pursue other entrepreneurial opportunities, will be replaced by Ruchir Sharma, an executive with MSDWIM, at the end of January.
Sharma, who has been a member of the global emerging markets team at MSDWIM since 1996, will be responsible for the Morgan Stanley Growth Fund, in his new position.
He will continue to work closely with New York-based Robert Meyer, managing director and head of emerging market equities, and his team.
According to a statement issued by MSDWIM, the company doesn't expect the new appointment to impact negatively on the fund's performance.