胡同（拼音：hú tong），为中国北方特有称呼，指狭窄的街道。其中又以北京的胡同最为著名。

根据史料记载，胡同一词最初见于元杂剧。元代杂曲名家关汉卿的《单刀会》中，有“杀出一条血胡同来”的台词。元杂剧《沙门岛张生煮海》中也有如下对白:“张羽问梅香：‘你家住哪里？’梅香说：‘我家住砖塔儿胡同。’”其中提到的砖塔儿胡同就是今天的砖塔胡同。

明沈榜所着《宛署杂记》中记载：胡同本元人语。

根据史料记载和民间传说，目前学术界对“胡同”一词含义和来源的解释主要有以下几种：

Hutongs (simplified Chinese:胡同; traditional Chinese:胡同; pinyin:hútòng; Wade–Giles:hu-t'ung) are a type of narrow streets or alleys, commonly associated with northern Chinese cities, most prominently Beijing.

In Beijing, hutongs are alleys formed by lines of siheyuan, traditional courtyard residences. Many neighbourhoods were formed by joining one siheyuan to another to form a hutong, and then joining one hutong to another. The word hutong is also used to refer to such neighbourhoods.