Mercury retrograde is the astrological belief that when the planet Mercury appears to move backward in the sky, it causes widespread disruption—particularly in communication, transportation, technology, and decision-making. Though the retrograde is a visual illusion caused by differences in planetary orbits, astrology attributes real-world effects to the perceived reversal. Commonly reported issues during this period include broken electronics, travel delays, missed messages, and contractual misunderstandings.

Mercury is traditionally associated with the Roman god of commerce, communication, and travel. In astrology, the planet governs speech, writing, scheduling, negotiation, and mobility. When its apparent movement reverses, astrologers believe the energy governing these areas becomes unstable, making it a poor time for major decisions or technological upgrades. These beliefs are documented in classical astrological texts dating back to Babylonian and Greek interpretations of planetary influence.