Atlanersa (also Atlanarsa) was a Kushite ruler of the Napatan kingdom of Nubia, reigning for about a decade in the mid-7th century BC. He was the successor of Tantamani, the last ruler of the 25th Dynasty of Egypt, and possibly a son of Taharqa or less likely of Tantamani, while his mother was a queen whose name is only partially preserved. Atlanersa's reign immediately followed the collapse of Nubian control over Egypt, which witnessed the Assyrian conquest of Egypt and then the beginning of the Late Period under Psamtik I. The same period also saw the progressive cultural integration of Egyptian beliefs by the Kushite civilization.

Atlanersa may have fathered his successor Senkamanisken with his consort Malotaral, although Senkamanisken could also be his brother. He built a pyramid in the necropolis of Nuri, now conjecturally believed to be Nuri 20 and may also have started a funerary chapel in the same necropolis, now called Nuri 500. Atlanersa was the second Nubian king to build a pyramid in Nuri after Taharqa. Excavations of his pyramid produced many small artefacts which are now on display in the Museum of Fine Arts in Boston, US. Atlanersa's most-prominent construction is his temple to the syncretic god Osiris-Dedwen in Jebel Barkal called B700, which he finished and had time to only partially decorate. This suggests that he died unexpectedly. The temple entrance was to be flanked with two colossal statues of the king, one of which was completed and set in place and is now in the National Museum of Sudan.

Atlanersa was the son of king Taharqa or less probably of Atlanersa's immediate predecessor Tantamani. Specialists, such as László Török, who contend that Atlanersa's father was Taharqa, explain the intervening reign of Tantamani by positing that Atlanersa might have been too young to ascend the throne at the death of his father and that attempting a military reconquest of Egypt required a strong king. A cultural explanation is also possible: Napatan society might have recognized seniority and maturity as valid arguments for inheriting a throne. In this sense a young heir to the throne would be overlooked in favor of someone older until they reached maturity. At this point, should the king die, the right to the throne of the original heir would be reinstated. If Atlanersa was indeed a son of Taharqa, then he was a cross-cousin of Tantamani.

Atlanersa's mother was a queen who appeared on a pylon scene at Jebel Barkal Temple B700 but whose name is not fully preserved and is only known to have ended in [...]salka. She bore the title of "Great one of the Imat-scepter, noblewoman".

Atlanersa was married to at least two of his sisters: Yeturow, who bore the title of "wife of the king, daughter of the king, sister of the king, mistress of Egypt", and Khaliset (also known as Khalese) who was "noblewoman, lady of the Imat-sceptre, singer, great daughter of the king". Khaliset was intended to be the mother of Atlanersa's heir, as indicated by her titles, but it may have been another of Atlanersa's consorts, Malotaral "mistress of Kush", who was the mother of Atlanersa's heir Senkamanisken. Further potential consorts of Atlanersa have been identified: his sister Peltasen and queens K[...] and Taba[...]. Finally, there is a distinct possibility that Amenirdis II, the Divine Adoratrice of Amun in Thebes, was married to Atlanersa. In addition, she may have been his sister.

One daughter of Atlanersa by one of his wives is known: Queen Nasalsa, sister-wife of Senkamanisken and mother of Anlamani and Aspelta. It is also possible that Queen Amanimalel was his daughter. Atlanersa's successor Senkamanisken may have been his son, but could instead have been his brother.

Foundation tablets bearing Atlanersa's name show that he started a temple dedicated to the syncretic god Osiris-Dedwen at Jebel Barkal, now known as B700. The choice for this location followed from its closeness to the "Pure Mountain"—the ancient name of Jebel Barkal—and the presence of a small New Kingdom chapel there. It is unclear whether Atlanersa ordered the destruction of this chapel to make place for B700, or whether the chapel was already ruined by this time.

The temple, now ruined, was entered through a pylon and comprised a small court followed by an inner sanctuary. The court and sanctuary both had four columns, with palm capitals and papyrus flower bundle capitals, respectively. The inner sanctuary was inscribed with a lengthy hymn to Osiris, possibly indirectly referring to the deceased Taharqa. The walls were further decorated with reliefs depicting the activities performed during the coronation of the king, almost all of which have now disappeared. Beneath two of the corners of the inner room were two foundation deposits buried at the start of the temple construction, notably with the tablets showing Atlanersa's name. A stand for a sacred barque stood at the centre of the sanctuary. The stand is made of a single block of granite weighing over 8 t (8.8 short tons). The purpose of the stand was to support the barque of the god Amun of Napata when it visited the temple from the nearby Temple B500.