Certainly.
When the UN was started way back.... There's a treaty of nations back in 1917 that actually referred to equal pay at that point. That's why we say it's one of the first standards.
The ILO Convention 100, which Canada ratified in 1972, is the main “equal pay for work of equal value” standard. That standard is also part of what's called the “core labour standards”, which world governments and the UN have all said are the basic standards that need to be implemented.
In addition, the UN Covenant on Economic, Social and Cultural Rights also includes equal pay for work of equal value as one of the main contexts of that set of economic, social, and cultural rights.
The Beijing Declaration of the UN World Conference on Women, which is updated every five and ten years by world governments, also includes equal pay for work of equal value.