Autoimmune polyendocrine syndromes (APSs), also called polyglandular autoimmune syndromes (PGASs) or polyendocrine autoimmune syndromes (PASs), are a heterogeneous group of rare diseases characterized by autoimmune activity against more than one endocrine organ, although non-endocrine organs can be affected.

Autoimmune polyendocrine syndrome type 1, is a subtype of autoimmune polyendocrine syndrome (autoimmune polyglandular syndrome).

Autoimmune polyendocrine syndrome type 2, a form of autoimmune polyendocrine syndrome also known as APS-II, or PAS II, is the most common form of the polyglandular failure syndromes.