Hassan Diab (Arabic: حَسَّان دِيَاب, romanized: Hassân Diyâb; born 1 June 1959) is a Lebanese academic, engineer and politician who served as the prime minister of Lebanon from 21 January 2020 to 10 September 2021.

[1][2] He submitted his resignation on 10 August 2020 in wake of the 2020 Beirut explosion and served as caretaker prime minister until Najib Mikati formed a new government on 10 September 2021.

[6] Lebanon's new government was formed on 21 January 2020 after Diab and Parliament Speaker Nabih Berri met with President Michel Aoun.

[10][11] Diab then announced the new twenty-member cabinet made up of technocrats reporting that they would work on new election law, seeking an independent judiciary and the return of looted public funds.

[20] Before the Monday, August 10 meeting, five ministers out of the cabinet's twenty tendered their resignation, two less than the seven required by the Lebanese Constitution to force the whole cabinet's resignation, in what was later declared by politicians close to Parliament Speaker Nabih Berri and President Michel Aoun to have been a reaction to Diab's proposed bill.

Due to Aoun's refusal to discuss the early elections bill, the meeting took place in the Grand Sérail instead of the Baabda Presidential Palace.