The temple of Hera, one of the oldest monumental temples in Greece, stands in the north-west corner of the sacred precinct of the Altis, on the south slopes of Kronios hill, protected by a powerful terrace wall. It was dedicated to the Olympian sanctuary by the inhabitants of Skillous, an ancient city of Eleia. Pausanias relates that the temple was built approximately eight years after Oxylos ascended to the throne of Elis, that is c. 1096 BC, but in reality it is much later. According to some scholars, the first Heraion, built around 650 BC, was a small Doric temple with only a cella and pronaos, to which the opisthodomos and ptero were added later, around 600 BC. However, the theory that the entire temple was built around 600 BC prevails today. The temple was refurbished on many occasions, and the Romans transformed it into a kind of museum for the sanctuary's choicest treasures, such as the famous Hermes by Praxiteles.

The temple, which has a characteristic squat appearance owing to its great length in proportion to its breadth and its low height, is orientated east-west. It was a Doric peripteral hexastyle with sixteen columns at the sides. The original wooden columns were gradually replaced by stone ones, which belong to every period from the Archaic to Roman times, and display the full development of the Doric style. Even when Pausanias visited the temple in the second century AD, a wooden (oak) column was still in place at the opisthodomos. The columns had shallow cavities where painted portraits of the winners at the Heraia games were placed. The lower part of the temple was of shell-limestone and the upper part of mud brick. The entablature was of wood with terracotta revetment and terracotta tiles. The central circular akroterion, also of terracotta and 2.3 metres in diameter, had impressive painted decoration.

The temple was divided into three chambers: pronaos, cella and opisthodomos. Both the pronaos and opisthodomos were distyle in antis. The cella, which is entered through the pronaos by a double door 2.90 metres wide, was divided longitudinally by two rows of Doric columns. Every second column was engaged in an internal cross-wall, the four cross-walls defining five niches. On a pedestal at the far end of the cella stood the cult statues of Zeus and Hera, mentioned by Pausanias (V, 17, 1). Zeus was depicted standing next to Hera who was seated on a throne. The Archaic stone head of Hera recovered near the Heraion and displayed in the Olympia Archaeological Museum is attributed tentatively to this group. This is where the sixteen noble Elean women who organized the Heraian games, deposited a new peplos woven for the goddess every four years. The temple is known to have held the Disk of Iphitos on which the Olympic truce was incribed, while in the opisthodomos were the Chest of Kypselos made of wood, gold and ivory, and decorated with mythological scenes, and the Table of Kolotes on which the Olympic victors' wild olive crowns were displayed.

Only the temple's basement with its massive orthostates and lower part of the columns are visible in situ. Fragments of the terracotta entablature and the central akroterion are displayed in the museum.