莱得利基虫目（Redlichiida）是属于三叶虫纲的三叶虫，为比较原始的种类，出现在寒武纪早期。莱得利基虫目也是目前已知最早出现在化石上的节肢动物。

属于莱得利基虫目的三叶虫类通常拥有一个巨大且呈现半圆的头部、多环节的胸部与较小的尾部，而且通常也有一个大又突出，呈现半月形的眼睛。

Redlichiida is an order of trilobites, a group of extinct marine arthropods. Species assigned to the order Redlichiida are among the first trilobites to appear in the fossil record, about halfway during the Lower Cambrian. Due to the difficulty to relate sediments in different areas, there remains some discussion, but among the earliest are Fallotaspis (suborder Olenellina), and Lemdadella (suborder Redlichiina), both belonging to this order. However, the first representatives of the orders Corynexochida and Ptychopariida also appear very early on and may prove to be even earlier than any redlichiid species. However, in terms of anatomical comparison, the earliest redlichiid species are probably ancestral to all other trilobite orders and share many primitive characters. The last redlichiid trilobites died out before the end of the Middle Cambrian.