Yi An-sa

{{family name hatnote|Yi||lang=Korean}}

{{Infobox royalty

| name = Yi Ansa
이안사
李安社

| title = King of Joseon (posthumously)

| image =

| caption =

| succession = Darugachi

| reign = 1252–1274

| birth_name = Yi Ansa ({{Korean|hangul=이안사|labels=no}})

| birth_date = 1204

| birth_place = Jeonju, North Jeolla Province, Goryeo

| death_date = 3 March 1274 (aged 69-70)

| death_place = Jeonju, North Jeolla Province, Goryeo

| burial_date =

| burial_place = Deokneung tomb

| spouse = Queen Hyogong (m. 1223)

| issue = 6 sons

| posthumous name = *First: King Mok (목왕, 穆王; given in 1392 by King Taejo)

• Last: King Inmun Seongmok the Great (인문성목대왕, 仁文聖穆大王; given in 1411 by King Taejong)

| temple name = Mokjo ({{Korean|hangul=목조|hanja=穆祖|labels=no}})

| royal house = House of Yi

| father = Yi Yang-mu

| mother = Lady Yi of the Samcheok Yi clan

| religion =

}}

Yi An-sa (1204 – 3 March 1274) was a Goryeo nobleman who would become the great-great-grandfather of Yi Seonggye, founder of the Joseon Dynasty.{{Citation needed|date=March 2024}}

On 28 July 1392, when Taejo made a new dynasty, he was granted the royal title King Mok ({{Korean|hangul=목왕|hanja=穆王|labels=no}}).{{Cite web|url=http://sillok.history.go.kr/id/kaa_10203010_001|script-title=ko:조선왕조실록|website=Veritable Records of the Joseon Dynasty}} After his death in 1274, he was buried in Deokneung, Neung-ri, Gapyeong-myeon, Sinhung-gun, South Hamgyong Province, North Korea and given the temple name Mokjo ({{Korean|hangul=목조|hanja=穆祖|labels=no}}) by his great-great-great-grandson, King Taejong on 22 April 1411 along with his posthumous name.{{Cite web|url=http://sillok.history.go.kr/id/kca_11702022_001|script-title=ko:조선왕조실록|website=Veritable Records of the Joseon Dynasty}}