António José Martins Seguro (born 11 March 1962) is a Portuguese politician for the Socialist Party (PS).

Seguro was Secretary General of the PS from 2011 until September 2014, and he was the leader of the largest opposition party in the Portuguese Parliament.

He attended the 1st cycle program in business organization and management at the ISCTE – Lisbon University Institute, but he did not graduate.

[3] In 1995, the Socialist Party won the parliamentary elections, leaving the leader António Guterres to form a government.

He also played the role of coordinator of the Standing Committee of the Portuguese Socialist Party and president of the Municipal Assembly of Penamacor.