The service will initially be family-focused, drawing on Pixar and Disney fare and including productions from the Disney Channel and Disney Junior.
Disney is launching its service in the US, but chief executive Bob Iger told analysts to think of it as a global service.
The company is also launching a streaming service for ESPN, the sports network with rights to top flight-competitions including Major League Baseball and the NFL.
Disney is to pull its movies from Netflix and take on the streaming company with the launch of its own service from 2019, showing family-friendly fare such as the Toy Story films, Frozen and its forthcoming sequel, and The Lion King.