Mohammad Reza Shajarian (Persian: محمد رضا شجريان) (born September 23, 1940 in Mashhad, Iran) is an internationally and critically acclaimed Persian traditional singer, composer and ostad (master) of Persian music. He has been called "Iran's greatest living master of traditional Persian music." Shajarian is also known for his skills in Persian calligraphy, and humanitarian activities.

Shajarian has collaborated with Parviz Meshkatian, Mohammad Reza Lotfi, Hossein Alizadeh, and Faramarz Payvar. He is recognised as skilled singer in the challenging traditional Dastgah style. In 1999 UNESCO in France presented him with the Picasso Award. Early work Shajarian studied singing at the early age of five under the supervision of his father, and at the age of twelve, he began studying the traditional classical repertoire known as the Radif. Shajarian started his singing career in 1959 at Radio Khorasan, rising to prominence in the 1960s with his distinct style of singing. Since then his career has included teaching at Tehran University's Department of Fine Arts, working at National Radio and Television, researching Iranian music, and making numerous recordings. Music Groups Shajarian has not always been in music groups, but he currently does the vocals for the Masters of Persian Music with his son Homayoun Shajarian, as well as two other ostads, Keyhan Kalhor and Hossein Alizadeh.