ث

'''' () is the fourth letter of the Arabic alphabet, one of the six letters not in the twenty-two akin to the Phoenician alphabet (the others being , , , , ). It is related to the Ancient North Arabian 𐪛‎‎‎‎, and South Arabian .

In Modern Standard Arabic it represents the voiceless dental fricative , also found in English as the "th" in words such as "thank" and "thin". In Persian, Urdu, and Kurdish it is pronounced as s as in "sister" in English. Ṯāʾ, along those with the letter shīn, are the only two surviving Arabic letters with three dots above. In most European languages, it is mostly romanized as the digraph th. In other languages, such as Indonesian, this Arabic letter is often romanized as ts and Ṡ.