| Native Name: | ফসিউদ্দিন মাহতাব |
| Native Name Lang: | bn |
| Office1: | Minister of Finance |
| Termstart1: | 12 February |
| Termend1: | 24 March 1982 |
| President1: | Abdus Sattar |
| Primeminister1: | Shah Azizur Rahman |
| Office2: | Minister of Agriculture |
| Termstart2: | 28 November 1981 |
| Termend2: | 11 February 1982 |
| President2: | Abdus Sattar |
| Primeminister2: | Shah Azizur Rahman |
| Office3: | Minister of Planning |
| Termstart3: | 15 April 1979 |
| Termend3: | 27 November 1981 |
| President3: | Ziaur Rahman Abdus Sattar (acting) |
| Primeminister3: | Shah Azizur Rahman |
| Office4: | State Minister of Agriculture and Forest |
| Termstart4: | 29 June 1978 |
| Termend4: | 6 April 1979 |
| President4: | Ziaur Rahman |
| Primeminister4: | Mashiur Rahman (acting) |
| Nationality: |  Bangladesh |
| Birth Place: | Chapai Nawabganj, Rajshahi Division, Bangladesh |
| Death Place: | London, United Kingdom |
| Resting Place: | Banani Graveyard, Dhaka, Bangladesh |
| Father: | Mahtabuddin Sarker |
| Spouse: | Hajera Mahtab |
| Party: | Bangladesh Nationalist Party |
Fasihuddin Mahtab (bn|ডঃ ফসিউদ্দিন মাহতাব), also spelt Fashiuddin Mahtab, was a Bangladeshi researcher, social worker and the secretary-general of BIRDEM and Diabetic Association of Bangladesh, as well as a member of President Ziaur Rahman's advisory council and later technocrat minister.[1] [2] [3] He was also the son-in-law of BIRDEM founder Muhammad Ibrahim, who was also a member of the advisory council.[4]
In late 1970s, Mahtab served as a minister of state for agriculture during Ziaur Rahman's presidency before being promoted to cabinet minister. He served variously as Planning Minister, Agriculture Minister and Finance Minister as a member of the Bangladesh Nationalist Party (BNP) in the 2nd legislative session of the Jatiya Sangsad.[5]
Mahtab was born to Bangladeshi politician and magistrate and East Pakistani MP of the national assembly Mahtabuddin Sarker.[6] He was married to Ibrahim's daughter Hajera Mahtab.
Mahtab died on September 22, 2008, at Leeds Hospital in London and was buried at the Banani Graveyard in Dhaka.