Nketiah, 21, is the latest high-profile footballer to receive racist abuse on social media. He was sent the racist message telling him to leave Arsenal.
Speaking at the Financial Times Business of Football summit on Thursday, Arsenal chief executive Vinai Venkatesham called on authorities and social media companies to "wake up" and not underestimate the impact the abuse has on victims.
A spokesperson for Twitter told Sky Sports News: "Racist behaviour has no place on our service and when we identify accounts that violate any of the Twitter Rules, we take enforcement action. The account referenced has been permanently suspended."