Ṭā Hā (/ˈtɑːˈhɑː/; Arabic: طه) is the 20th chapter (sūrah) of the Qur'an with 135 verses (āyāt). It is named "Ṭā Hā" because the chapter starts with the Arabic ḥurūf muqaṭṭaʿāt (disjoined letters) طه (Ṭāhā), which is widely mistaken to be one of the names of the Islamic prophet Muhammad, but is just one of the many unlinked letters at the beginning of many other surahs of the Quran.
Regarding the timing and contextual background of the revelation (asbāb al-nuzūl), it is traditionally believed to be a Meccan surah, from the second Meccan period (615-619), which means it is believed to have been revealed in Mecca, rather than later in Medina.