Rabiʽ al-Thani (Arabic: رَبِيع ٱلثَّانِي, romanized: Rabīʿ ath-Thānī, lit. 'The second Rabi', also known as Rabi' al-Akhirah (Arabic: رَبِيع ٱلْآخِرَة, romanized: Rabi' al-ʾĀkhirah, lit. 'The final Rabi'), Rabiʽ al-Akhir (Arabic: رَبِيع ٱلْآخِر, romanized: Rabīʿ al-ʾĀkhir), or Rabi' II is the fourth month of the Islamic calendar. The name Rabī' al-Thani means "the second spring" in Arabic, referring to its position in the pre-Islamic Arabian calendar.

The word "Rabi" means "spring" and Al-thani means "the second" in the Arabic language, so "Rabi' al-Thani" means "the second spring" in Arabic. As the Islamic calendar is a purely lunar calendar, the month naturally rotates over solar years, so Rabīʽ al-Thani can fall in spring or any other season. Therefore, the month cannot be related to the actual season of spring.^[1]

The Islamic calendar is a purely lunar calendar, and months begin when the first crescent of a new moon is sighted. Since the Islamic lunar year is 11 to 12 days shorter than the tropical year, Rabī' al-Thānī migrates throughout the seasons. The estimated start and end dates for Rabī' al-Thānī are as follows (based on the Umm al-Qura calendar of Saudi Arabia^[2]):

• 08 or 10 Rabī' al-Thānī, the birth of the Eleventh Imam Hasan al-Askari
• 10 or 12 Rabī' al-Thānī, death of Fatimah bint Musa
• 11 of Rabī' al-Thānī, death of Abdul-Qadir Gilani, the Sufi sheikh who is believed to be the "saint of saints"
• 15 of Rabi' al-Thani, death of Habib Abu Bakr al-Haddad
• 27 of Rabi' al-Thani, death of Ahmad Sirhindi
• 28 or 29 of Rabī' al-Thānī, death of ibn Arabi, the great philosopher from Spain who died and rests in Damascus, Syria.^[3]

• Islamic-Western Calendar Converter (Based on the Arithmetical or Tabular Calendar)