IHSS may refer to:
Honduran Social Security Institute (Instituto Hondureño de Seguridad Social in Spanish), social security in Honduras Idiopathic hypertrophic subaortic stenosis, an older term for hypertrophic obstructive cardiomyopathy (HOCM) International Humic Substances Society, a scientific society that seeks to advance knowledge and research of natural organic matter In-Home Supportive Services (IHSS) program, in-home help for aged, blind, and disabled people as an alternative to out-of-home care in California