Sena (Thai: เสนา, pronounced [sěːnāː]) is a district (amphoe) in Phra Nakhon Si Ayutthaya province, central Thailand.

Local people typically know the populated centre of Sena as Ban Phaen (บ้านแพน).

[1] Neighboring districts are (from the north clockwise) Phak Hai, Bang Ban, Bang Sai (บางไทร), Lat Bua Luang and Bang Sai (บางซ้าย) of Ayutthaya Province.

The district is divided into 17 sub-districts (tambon), which are further subdivided into 132 administrative villages (muban).

There are a further nine tambon administrative organizations as the local government for the sub-districts not part of a municipality.