The director screened his Academy Award-nominated film at the UN on Wednesday, after which the secretary-general said he had "become speechless after having seen this very powerful movie..."
"There were moments when the film was very hard to watch. But there can be no turning away -- not from the horrors of slavery as it was practiced then, and not from the forms of slavery that exist today around the world."
Ban Ki-moon drew a parallel between the movie's depiction of slavery in the pre-Civil War United States and modern human trafficking.
"Millions of people of both sexes are being exploited -- forced into debt bondage, sexual slavery and other vile practices. All too often the predators operate with impunity."
He expressed hope that McQueen's film "will inspire many years of action to end all forms of slavery for good."