Phasi Charoen (Thai: ภาษีเจริญ, pronounced [pʰāː.sǐː t͡ɕā.rɤ̄ːn]) is one of the 50 districts (Khet) of Bangkok, Thailand. The district is bounded by other Bangkok districts (from north clockwise): Taling Chan, Bangkok Noi, Bangkok Yai, Thon Buri, Chom Thong, Bang Bon, and Bang Khae.

The name of the district came from a canal, Khlong Phasi Charoen (คลองภาษีเจริญ), linking Tha Chin River to Khlong Bangkok Yai. The canal project was initiated by Phra Phasi Sombat Boribun (พระภาษีสมบัติบริบูรณ์), who later became Phraya Phison Sombat Boribun (พระยาพิสณฑ์สมบัติบริบูรณ์). Originally Phasi Charoen proposed to fund the project in exchange for the right to collect tolls for passage. It was approved by King Mongkut, however, with the fund given via tax deduction from the amount Phra Phasi Sombat Boriboon had to collect, thus making the canal toll-free. Construction began in 1866 and was completed in 1872 and the canal was named after the man who had overseen the project.

The district was established as Amphoe Phasi Charoen in 1899. It became Khet Phasi Charoen in 1972.

The district is divided into seven sub-districts (khwaeng).

The missing number 3, 4 and 5 belong to the sub-districts which were split off to form Bang Khae district.