Tezcatlipoca (Classical Nahuatl: Tēzcatlīpohca [teːs̻kat͡ɬiːˈpoʔkaˀ]) or Tezcatl Ipoca was a central deity in Aztec religion. He is associated with a variety of concepts, including the night sky, hurricanes, obsidian, and conflict. He was considered one of the four sons of Ometecuhtli and Omecihuatl, the primordial dual deity. His main festival was Toxcatl, which, like most religious festivals of Aztec culture, involved human sacrifice.

Tezcatlipoca's nagual, his animal counterpart, was the jaguar. In the form of a jaguar he became the deity Tepeyollotl ("Mountainheart"). In one of the two main Aztec calendars (the Tonalpohualli), Tezcatlipoca ruled the trecena 1 Ocelotl ("1 Jaguar"); he was also patron of the days with the name Acatl ("reed"). A strong connection with the calendar as a whole is suggested by his depiction in texts such as the Codex Borgia and Codex Fejéváry-Mayer, where Tezcatlipoca is surrounded by day signs, implying a sort of mastery over them.

A talisman related to Tezcatlipoca was a disc worn as a chest pectoral, called the anahuatl. This talisman was carved out of abalone shell and depicted on the chest of both Huitzilopochtli and Tezcatlipoca in codex illustrations.

The origins of Tezcatlipoca can be traced to earlier Mesoamerican deities worshipped by the Olmec and Maya. Similarities exist between Tezcatlipoca and the patron deity of the K'iche' Maya, Tohil, as described in the Popol Vuh. The name Tohil refers to obsidian and he was associated with sacrifice. The Classic Maya god of rulership and thunder, K'awiil, was depicted with a smoking obsidian knife in his forehead and one leg replaced with a snake. Although there are striking similarities between possible earlier imagery of Tezcatlipoca, archaeologists and art historians are split in the debate. It is possible that he is the same god that the Olmec and Maya term their "jaguar deity", or alternately that he is an Aztec expansion on foundations set by the Olmec and Maya, as the Aztecs routinely took deliberate inspiration from earlier Mesoamerican cultures.

Tezcatlipoca is often translated from the Nahuatl as "smoking mirror." It alludes to his connection to obsidian, the material from which mirrors were made in Mesoamerica. They were used for shamanic rituals and prophecy, and as such Tezcatlipoca is additionally associated with divination.

Tezcatlipoca had many epithets which alluded to different aspects of his deity and also point to his centrality in Aztec worship. Bernardino de Sahagún, in Book VI of the Florentine Codex, refers to Tezcatlipoca with 360 different forms. These include:

Few representations of Tezcatlipoca survive into the present day, due in large part to a significant portion of codices being destroyed by Catholic priests. Simultaneously, some Aztec texts note that the darkness and omnipresence of Tezcatlipoca make him something akin to "invisible", thus direct representations of him are considered inadequate or even impossible. Still, multiple depictions of the deity exist, and common trends and symbols can be identified.

One of the most recognizable iconographic details of Tezcatlipoca is his face paint, called mixchictlapanticac. Most commonly, he is shown with horizontal bands of black and yellow, though codices may vary in which two colors are depicted. Mary Miller has posited that the combination of yellow and black might be a connection to the jaguar, with which Tezcatlipoca is associated. Black is the foremost color associated with Tezcatlipoca, not only because of his role as a god of nighttime and darkness, but to differentiate him from the other three so-called Tezcatlipocas (Quetzalcoatl, Huitzilopoctli, and Xipe-Totec) and their respective colors (white, blue, and red). Which parts of his body are painted black varies by site; half of his leg, the full length of his arms, the majority of his legs, or any combination thereof can be depicted. Later scholarship has identified the black material with which the god was supposedly painted as tezcatlipoctli. He is often depicted with various symbolic objects in place of his right foot, such as an obsidian mirror, bone, or a serpent. This is an allusion to the creation myth, in which Tezcatlipoca loses his foot battling with the earth monster Cipactli. The obsidian mirror may also appear on his chest, as a breastplate, and often is shown emanating smoke — a literal representation of his name and role. In the majority of representations, Tezcatlipoca bears the mirror in one hand, where it is surrounded by feathers of various colors.