Þ、þ（þorn 或 thorn）是古英语和冰岛语的一个字母。这字母也曾在中世纪斯堪的纳维亚使用，但在现代英语和斯堪的纳维亚各语言均已被 th 所取代。 þ 来自如尼字母 ᚦ (U+16A6) ，在古英语称为 þorn，在斯堪的纳维亚称为 thurs（北欧神话的巨人）。

在冰岛语中，这个字母排在字母表的第 30 位，表示 /θ/ 音。 在Windows系统中，按 alt 键不放同时按数字键0222，就会打出Þ，而按数字键0254，就会打出þ。

Thorn or þorn (Þ, þ) is a letter in the Old English, Gothic, Old Norse and modern Icelandic alphabets, as well as some dialects of Middle English. It was also used in medieval Scandinavia, but was later replaced with the digraph th, except in Iceland, where it survives. The letter originated from the rune ᚦ in the Elder Fuþark and was called thorn in the Anglo-Saxon and thorn or thurs (a category of beings in Germanic paganism) in the Scandinavian rune poems. Its reconstructed Proto-Germanic name is Thurisaz.