| Honorific-Prefix: | Osmancıklı / Amasyalı · Koca |
| Mehmed Nizamüddin | |
| Office: | 10th Grand Vizier of the Ottoman Empire |
| Term Start: | 28 August 1429 |
| Term End: | 1438 |
| Predecessor: | Çandarlı Ibrahim Pasha the Elder |
| Successor: | Çandarlı Halil Pasha the Younger |
| Death Date: | 1439 |
| Death Place: | Osmancık, Ottoman Empire |
| Nationality: | Ottoman |
Osmancıkli (or Amasyali) Koca Mehmed Nizamüddin Pasha (Turkish: Osmancıklı [[Danishmends|Danişmendoğlu]] Koca Mehmet Nizamüddin Paşa; died 1439) was an Ottoman statesman who served as grand vizier of the Ottoman Empire from 1429 to 1438.[1]
He settled in Osmancık after his service as grand vizier and died there in 1439. He was the son of Imamzade Halil Pasha, who also served as grand vizier.