Religion is a cultural feature in which intelligent beings display a belief in and/or reverence for a higher power. This belief is often evidenced by lifestyle that includes worship. Various cultures on Sonic's World are known to practice one form of religion or another.
- Illumina - A entity that governs Maginary World, a world entirely made up of people's dreams. Having lost faith in herself, she split into two beings representing the different sides of her nature: the benevolent Lumina and the villainous Void. It is not known if any groups hold Illumina in reverence.
- Ixis - A powerful dark deity worshiped by Trolls. Wellsprings of Ixis' energy can be found on Sonic's World, although finding them can be a feat.
- Light Gaia/Dark Gaia - Two primordial titans who follow constant cycle. Dark Gaia awakens once every couple of millions of years to destroy the earth and Light Gaia then restores it in an event known as the "time of awakening". The two would then return to sleep in the Earth's core until they can reawaken to continue the cycle. Light Gaia is known to have some adherents, such as Gregorios and his associates.
- Solaris - A powerful being with fire and time-based powers worshiped as a sun god by the inhabitants of Soleanna. A series of experiments caused it to split into Iblis and Mephiles.
- Spirits - Certain populations on Sonic's World, most notably the inhabitants of Meropis, believe in the existence of protective spirits and regard them with great respect. Among those classified as spirits are Tikal and Chaos. Individuals who are favored by these spirits are also treated with great respect, as seen in the case of Aquarius the Chao. But there also exist malevolent spirits which seek to spread misery and chaos, such as the legion of Dark Gaia's Minions.
- Many supernatural beings in the Sonic universe demonstrate themes of duality:
- The monster Iblis shares its name with the Islamic version of the devil, and the Ifrit also shares its name with an Islamic figure.