Abdul Aziz Al ash-Sheikh is a member of the Saudi Arabian family Al ash-Sheikh. He is the descendant of founder of Wahhabism, Muhammad ibn Abdul Wahhab Najdi.
In June 1999, he was appointed Grand Mufti of Saudi Arabia by King Fahd, succeeding Abdul Aziz ibn Baaz.
Following Pope Benedict XVI's quotation of a Byzantine emperor in a lecture, he called the pope's statement "lies", adding that they "show that reconciliation between religions is impossible".
In 2007, he announced plans to demolish the Green Dome and flatten the tombs housed under it, including that of Muhammad.
On 15 March 2012, he declared that, "All churches in the Arabian Peninsula must be destroyed". His declaration about the destruction of churches in the Arabian Peninsula led to negative comments. Roman Catholic bishops in Germany and Austria responded sharply to his fatwa, concerned about the human rights of non-Muslims working in the Persian Gulf region. Russian Orthodox Archbishop Mark of Yegoryevsk said the ruling was "alarming". Most of the world overlooked the statement. Mehmet Görmez, the most senior imam in Turkey, another Muslim country, blasted the Saudi grand mufti’s call to “destroy all the churches” in the Persian Gulf region, saying that the announcement totally contradicted the peaceful teachings of the Muslim religion. Görmez, the president of Diyanet İşleri Başkanlığı (Presidency of Religious Affairs), said he could not accept the Islamic religious order—fatwa—issued by Grand Mufti Sheikh Abdulaziz Al ash-Sheikh, adding that the mufti’s declaration ran contrary to the centuries-old Islamic teachings of tolerance and the sanctity of institutions belonging to other religions.
In April 2012, he issued a fatwa allowing ten-year-old girls to marry insisting that girls are ready for marriage by age 10 or 12: "Our mothers and grandmothers got married when they were barely 12. Good upbringing makes a girl ready to perform all marital duties at that age." However, he is opposed to the practice of marrying off very young girls to older men, emphasizing its in-congruence with Islamic tradition.
In June 2013, he issued a fatwa demanding the destruction of statues of horses placed in a roundabout in Jizan: "The sculptures [must] be removed because they are a great sin and are prohibited under Sharia (Islamic law)".
The Grand Mufti issued a fatwa on September 12, 2013, that suicide bombings are "great crimes" and bombers are "criminals who rush themselves to hell by their actions". Sheikh described suicide bombers as "robbed of their minds... who have been used (as tools) to destroy themselves and societies."
In late August 2014, he condemned the Islamic State of Iraq and the Levant and al-Qaeda saying, "Extremist and militant ideas and terrorism which spread decay on Earth, destroying human civilisation, are not in any way part of Islam, but are enemy number one of Islam, and Muslims are their first victims".
On September 25, 2015, one day after the Mina crowd crush disaster which (according to the Associated Press) killed at least 1,399 foreign Muslims performing Hajj, Sheikh Abdul Aziz al-Sheikh publicly told Crown Prince Muhammad bin Nayef, who is also the country's Minister of Interior and responsible for Mecca safety and security, that he was "not responsible for what happened", and "as for the things that humans cannot control, you are not blamed for them. Fate and destiny are inevitable." With his words, the Grand Mufti immunized Muhammad bin Nayef from possible public criticism within Saudi Arabia, which set the official death toll for the Mina tragedy at fewer than 800 deaths.
In January 2016, while answering a question on a television show in which he issues fatwas in response to viewers’ queries on everyday religious matters, ruled that chess was forbidden in Islam because it constituted gambling, was a waste of time and money and a cause of hatred and enmity between the players.
In September 2016, the Grand Mufti ruled that all Muslims living in Iran are actually unbelievers, enemies of Islam, and "sons of the magians".
Abdul Razzaq al-Mahdi, Nabil Al-Awadi, Tariq Abdelhaleem, and Hani al-Sibai who are linked to Al-Qaeda, in addition to others like Adnan al-Aroor, Abd Al-Aziz Al-Fawzan, Mohamad al-Arefe, Abdul Rahman Al-Sudais, Abdul-Aziz ibn Abdullah Al Shaykh and others were included on a death list by ISIS.