The Advisory Committee of Experts on Slavery (ACE) was a permanent committee of the League of Nations, inaugurated in 1933. It was the first permanent slavery committee of the League of Nations, which was founded after a decade of work addressing the issue of slavery by temporary committees within the League.
The ACE conducted a global investigation concerning slavery, slave trade and force labor, and recommended solutions to address the issue. Its work lay the ground for the Supplementary Convention on the Abolition of Slavery of 1956.