Mehmet Zeki Sezer is a Turkish politician and former chairman of the Democratic Left Party (Demokratik Sol Parti, DSP), he was elected in the 6th ordinary party congress in 2004 after the resignation of Bülent Ecevit.
Sezer was born in 1957 in Eskişehir. He graduated from M. Rüştü Uzel Chemistry Vocational High School and then from the School of Chemical Engineering at Gazi Üniversitesi in Ankara. He completed his 4-month short-term military service in 1983.
During his high school and university years, Sezer played volleyball for various clubs. He has a special interest in arts. Sezer began his career as a chemistry technician in 1975 in the public service and later worked as a chemical engineer. He worked also in the private sector in the same capacity.
His political career in the DSP started in 1988. Sezer served as an executive of Çankaya branch of DSP, as deputy-chairman of Ankara branch and became a board member in 1991. He also served twice as the party's secretary-general. Between 2001 and 2004 he was the deputy chairman of DSP. In 2004 party congress succeeded Ecevit. However in 2009 he lost this post to Masum Türker.
In 1999, Sezer was elected as deputy of Ankara to the Parliament and served as a minister of state in the 57th government under the Prime minister Bülent Ecevit
Sezer is married and has two children.