- January 13: Panos Kammenos announces that Independent Greeks are pulling out of Tsipras' coalition government.
- January 16: PM Alexis Tsipras survives a no confidence vote by 151 to 148.
- January 19: Emmanouil Karalis (pole vault), Miltiadis Tentoglou (long jump) and Odysseas Mouzenidis (shot put) win gold medals at the first indoor Mediterranean Athletics U23 Championships in Miramas (France).
- January 20: An estimated 60,000 people protest against the Prespes agreement in Athens' Syntagma Square.
- January 20: Stefanos Tsitsipas upsets Roger Federer 3-1 sets in the round of 16 at the Australia Open.
- January 22: Stefanos Tsitsipas defeats Spaniard Roberto Bautista Agut 3-1 sets to advance to the semi-finals of the Australia Open.