自助注射器（英语：Autoinjector）是一种用于快速注射某类特定剂量药物（通常是急救药物）的医疗器械。

大多数的自助注射器都带有弹簧伸缩针头，这种设计可以使注射器更加便于使用，尤其是在没有任何旁人辅助，或者是注射者并未接受过医疗训练的情况下。使用自助注射器时，注射的位置应依照相关药物的特定要求。但在通常情况下，注射位置一般为大腿或臀部。相比起传统的针状注射器，自助注射器可以减低注射者替自身注射药物时的心理压力。

An autoinjector (or auto-injector) is a medical device designed to deliver a dose of a particular drug.

Most autoinjectors are spring-loaded syringes. By design, autoinjectors are easy to use and are intended for self-administration by patients, or administration by untrained personnel. The site of injection depends on the drug loaded, but it typically is administered into the thigh or the buttocks. The injectors were initially designed to overcome the hesitation associated with self-administration of the needle-based drug delivery device.