Helios was a Unix-like operating system for parallel computers developed and sold by Perihelion Software. It was most commonly used on various Transputer systems, but also supported other architectures. The system provided a micro-kernel that implemented a distributed name space and messaging protocol, through which services were accessed. A POSIX compatibility library enabled the use of Unix application software, and the system provided most of the usual Unix utilities.

Helios (; Helios; Latinized as Helius; in Homeric Greek) was the personification of the Sun in Greek mythology. He is the son of the Titan Hyperion and the Titaness Theia (Hesiod) (also known as Euryphaessa (Homeric Hymn 31)) and brother of the goddesses Selene, the moon, and Eos, the dawn.