Donal O'Sullivan may refer to:

• Donal O'Sullivan (artist) (1945–1991), Irish artist
• Donal Cam O'Sullivan Beare (1561–1613), last independent ruler of the O'Sullivan Beara clan
• Donal O'Sullivan (Gaelic footballer) (1930–2001), Irish Gaelic football player
• Donal O'Sullivan (politician) (1893–1973), Irish senator
• Donal O'Sullivan (priest) (1890–1916), Irish Catholic priest