Usually referred to as the Hephaisteion, the building was previously called the Theseion, a name still in common use. It has also been proposed that the temple was dedicated to Eukleia (Artemis). The temple was richly decorated. Planting pits dating from the 3rd century B.C. show that the temple grounds were fully landscaped. In the 7th century A.D. it was converted to a Christian church.
13.71 m x 38.24 m; intercolumniations: external columns 2.58 m (at the corners 2.41 m); lower diameter external columns: 1.02 m (at the corners 1.04 m); height external columns: 5.71 m.
| Archive Number | Caption |
| 1990.33.0099a | Plan |
| 1990.33.0100a | Plan, ca. 449-444 B.C. |
| 1990.20.0694 | Northeast face of the Acropolis with the Agora below, from E |
| 1990.30.0145 | Aerial view of Agora, from NW, with Hephaisteion, Acropolis, part of Areopagus |
| 1987.09.0324 | View from Acropolis |
| 1990.20.0527 | General view: Hephaisteion at top; Metroon lower right; steps of Propylon lower left, from SE |
| 1990.33.0101a | Elevation showing corner angle contraction |
| 1990.20.0540 | West end of New Bouleuterion with Temple of Hephaistos in distance, from S |
| 1990.20.0419 | Hephaisteion in distance, from SE |
| 1987.09.2034 | Overall view from SE |
| 1990.20.0322 | Distant view of the temple, from NE |
| 1990.20.0527 | General view: Hephaisteion at top; Metroon lower right; steps of Propylon lower left, from SE |
| 1990.20.0496 | View toward SW up the stairway leading to the Temple of Hephaistos on the Kolonos Agoraios Hill |
| 1990.20.0393 | Tholos in foreground; New Bouleuterion to left; Metroon to right; Hephaisteion in distance, from SE |
| 1990.20.0493 | View from N section of Metroon toward NW and monumental stairway to Temple of Hephaistos, from SE |
| 1990.20.0393 | Tholos in foreground; New Bouleuterion to left; Metroon to right; Hephaisteion in distance, from SE |
| 1990.20.0394 | View from Tholos (lower left), across the E side of the Metroon, toward N and temple of Hephaistos |
| 1990.20.0361 | View toward NW, across the Agora to the Hephaistaion |
| 1987.09.2030 | Temple and W side of Agora from Areopagus |
| 1990.20.0485 | Remains of steps leading up Kolonos Agoraios to Hephaisteion, from N |
| 1990.20.0351 | Northwest area of Agora with Hephaisteion on left, from S |
| 1990.20.0394 | View from Tholos (lower left), across the E side of the Metroon, toward N and temple of Hephaistos |
| 1990.20.0540 | West end of New Bouleuterion with Temple of Hephaistos in distance, from S |
| 1990.20.0424 | West Agora with Hephaisteion in background, from SE |
| 1987.09.0338 | View from SW |
| 1990.20.0393 | Tholos in foreground; New Bouleuterion to left; Metroon to right; Hephaisteion in distance, from SE |
| 1987.09.2032 | View from Stoa of Attalos |
| 1990.20.0493 | View from N section of Metroon toward NW and monumental stairway to Temple of Hephaistos, from SE |
| 1990.20.0694 | Northeast face of the Acropolis with the Agora below, from E |
| 1990.20.0441 | View from E end of South Stoa II towards NW and Hephaisteion |
| 1987.09.2033 | Temple of Hephaistos and Giants from Stoa of Attalos |
| 1990.20.0486 | Remains of steps leading up Kolonos Agoraios to Hephaisteion, from NE |
| 1990.20.0557 | View past NE corner of Temple of Hephaistos, from SE |
| 1990.20.0485 | Remains of steps leading up Kolonos Agoraios to Hephaisteion, from N |
| 1990.20.0694 | Northeast face of the Acropolis with the Agora below, from E |
| 1990.20.0573 | Front of the Temple of Hephaistos, from below and E |
| 1990.20.0393 | Tholos in foreground; New Bouleuterion to left; Metroon to right; Hephaisteion in distance, from SE |
| 1990.20.0394 | View from Tholos (lower left), across the E side of the Metroon, toward N and temple of Hephaistos |
| 1990.20.0578 | Entrance to temple, from E |
| 1990.20.0577 | Entrance to temple, from E |
| 1990.20.0558 | View through the entrance, from E |
| 1990.20.0557 | View past NE corner, from SE |
| 1990.20.0551 | The E, front colonnade, from S |
| 1987.09.0340 | East entablature and pediment |
| 1990.20.0556 | Southeast corner from SE |
| 1990.20.0548 | Southeast corner, from SE |
| 1990.20.0555 | West end of S side, from SE |
| 1990.20.0554 | East half of the S side, from S |
| 1990.20.0553 | South side, from E-SE |
| 1990.20.0549 | South side, from SE |
| 1990.20.0552 | South side colonnade, from SE |
| 1990.20.0550 | North side, from NE |
| 1987.09.0346 | Detail of central section of W frieze |
| 1987.09.0345 | Beams and frieze of W porch |
| 1987.09.0344 | Detail of S corner of west pediment |
| 1987.09.0343 | Metopes at E end of S entablature |
| 1987.09.0342 | Northeast corner with Apples of Hesperides metope |
| 1987.09.0341 | Southwest corner with Heracles and Lion metope |
| 1987.09.0339 | West half from SW |
| 1990.20.0351 | Northwest area of Agora with Hephaisteion on left, from S |
| 1990.20.0361 | View toward NW, across the Agora to the Hephaistaion |
| 1990.20.0424 | West Agora with Hephaisteion in background, from SE |
| 1990.20.0393 | Tholos in foreground; New Bouleuterion to left; Metroon to right; Hephaisteion in distance, from SE |
| 1990.20.0394 | View from Tholos (lower left), across the E side of the Metroon, toward N and temple of Hephaistos |
| 1990.20.0493 | View from N section of Metroon toward NW and monumental stairway to Temple of Hephaistos, from SE |
| 1990.20.0694 | Northeast face of the Acropolis with the Agora below, from E |
| 1990.20.0527 | General view: Hephaisteion at top; Metroon lower right; steps of Propylon lower left, from SE |
| 1990.20.0486 | Remains of steps leading up Kolonos Agoraios to Hephaisteion, from NE |
| 1990.20.0485 | Remains of steps leading up Kolonos Agoraios to Hephaisteion, from N |
| 1990.20.0441 | View from E end of South Stoa II toward NW and Hephaisteion |