Oelandocaris is an extinct genus of stem-mandibulate,[1] or possibly a megacheiran,[2] within the family Oelandocarididae.

Oelandocaris has a large head segment with a possible median eye, similar to peytoiids, making up roughly one half of its body.

[3] It has five tergites, each with a biramous limb pair and a spike on their ends, and a cylindrical tail segment.

As the exopods of Oelandocaris's limbs are large and flattened, it is very likely that it was a swimming animal, and presumably planktonic, based on its size.

Oelandocaris derives from the island of Öland in Sweden, a primary location for Orsten fossils, and the Greek word καρίς, meaning "shrimp" or "crab".