Theodoros Ziakas (Zakas, Zakkas) (Grevena 1798 - Atalanti 1882) was a chieftain in Macedonia during the Greek War of Independence in 1821.
His family were traditionally Armatoloi in Western Macedonia. When the Greek War of Independence broke out, Theodoros and his brother Yannulas, who was the successor in the leadership of "Ziakas' Armatoliki", begun the war to the Ottomans and liberated the region of Grevena. In 1826 Mehmet Agha leader of Ottoman military troops attacked and destroyed the headquarters of "Ziakas' Armatoliki" in Grevena. Yannulas Ziakas killed in that battle, but Theodoros got away in Southern Greece. Two years later, Theodoros Ziakas returned in Grevena region, took over the leadership of "Ziakas' Armatoliki" and established his new headquarters in Pindus mountains (Valia Kalda). He started a new war against the Ottomans until the end of the Greek War of Independence in the Grevena region, and after the establishment of the new Greek state he moved in Atalanti.
Theodoros Ziakas was a chieftain in northern Greece that was active in the Grevena region uprising against the Turks in 1854.