Sheikh Abdul Rahman bin Nasser Al-Saadi (Arabic: الشيخ عبد الرحمن بن ناصر السعدي), also known as al-Siʿdī (1889–1957), was an Islamic Scholar from Saudi Arabia.

[3] He served as the imam and khateeb for the largest jami' mosque[4] and director of the religious training school, al-Ma'had al-'Ilmi, of Unayzah.

He was initially cared for by his father's second wife[8] and was later transferred to the guardianship of his oldest brother, Hamad ibn Nasir al-Sa'di.

[10] al-Sa'di's teachers had studied in a number of different regions including the Hijaz, Egypt, Iraq, Syria, India and Mauritania.

[22] In Ramadan 1942/1361AH, he was appointed as the primary imam and khateeb for the city's largest jami' mosque,[4] a role which he held until his death in 1956/1376AH.

In 1956/1376AH, he authored a small work dedicated to clarifying the prohibitions of smoking and its spiritual, physical, and monetary harms.

[31] He regularly received and responded to letters asking for fatwa from other countries in the Arabian Peninsula and Indian Subcontinent.

[32][10] One large volume of al-Sa'di's fatawa that had been given in his letters and foreign correspondences was posthumously compiled and published under the time of al-Fatawa al-Sa'diyyah.

[20] Al-Sa'di's influence and popularity during his own lifetime has been, in part, attributed to his early embrace of new technologies for spreading religious knowledge.

[41] Upon hearing of his health problems, King Sa'ud sent two doctors via his personal jet to attend to sheikh al-Sa'di.

[46][45] al-Sa'di did not ultimately publish this book or mention any of the issues it contained in subsequent teaching or written works, though he is not known to have publicly renounced these positions.

[13] In November 2019, Qassim University hosted a two-day conference entitled "The Illustrious Sheikh 'Abdur-Rahman al-Sa'di and His Influence on Religious Knowledge and Propagation.

"[47][48] This conference was inaugurated by president of the General Presidency for the Affairs of the Two Holy Mosques Abdul-Rahman al-Sudais,[49] and also included speeches by Grand Mufti of Saudi Arabia Abdul-Aziz ibn Abdullah Al Shaykh, member of the Council of Senior Scholars Saad al-Shithri, and the governor of al-Qassim region.

[47] The stated goal of this conference was to cast light upon al-Sa'di legacy and encourage further research into his thought and legal reasoning.