Tenofovir disoproxil, sold under the trade name Viread among others, is a medication used to treat chronic hepatitis B and to prevent and treat HIV/AIDS. It is generally recommended for use with other antiretrovirals. It may be used for prevention of HIV/AIDS among those at high risk before exposure, and after a needlestick injury or other potential exposure. It is sold both by itself and together as emtricitabine/tenofovir and efavirenz/emtricitabine/tenofovir. It does not cure HIV/AIDS or hepatitis B. It is available by mouth as a tablet or powder.

Common side effects include nausea, rash, diarrhea, headache, pain, depression, and weakness. Severe side effects include high blood lactate and an enlarged liver. There are no absolute contraindications. It is often recommended during pregnancy and appears to be safe. It is a nucleotide reverse transcriptase inhibitor and works by decreasing the ability of the viruses to replicate.

Tenofovir was patented in 1996 and approved for use in the United States in 2001. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication as of 2017.