百夫长（英语：Centurion，拉丁语：Centurio，希腊语：κεντυρίων）是罗马军团中的职业军官，平时负责训练，战时负责指挥。大部分百夫长都各自领导一个百人队，但是也有较高等级的百夫长会领导一个步兵队，或者在军团中担任高级参谋的角色。

百夫长这个名称来自于他们所领导百人队。百人队在罗马军队一直是一个很重要的编制，其历史可以追溯到前6世纪的罗马王政时代。如同其名称一样，百人队最初大约由100人组成。后来百人队又变为了由60人组成，两个百人队组成一个小队（拉丁语：Manipulus），其中一个有较高的权威。在马略改革后，标准的百人队编制又变为80人。

A centurion (Latin:centurio; Greek: κεντυρίων, kentyríōn, or ἑκατόνταρχος, hekatóntarkhos) was a professional officer of the Roman army after the Marian reforms of 107 BC. Most centurions commanded groups of centuries of around 100 men but senior centurions commanded cohorts or took senior staff roles in their legion. Centurions were also found in the Roman navy. In the Byzantine Army, they are also known by the name kentarch (κένταρχος, kentarchos). Their symbol of office was the vine staff, with which they disciplined even Roman citizens protected from other forms of beating by the Porcian Laws.