Lydia Mei (2 July 1896 – 14 September 1965) was an Estonian artist known above all for her watercolors. She was born in Liepāja, then in the Courland Governorate of the Russian Empire and now in Latvia, the middle of three daughters of the Estonian navigator and hydrographer Johan Mey, who came from Hiiumaa. All three sisters became artists.
Mei studied architecture at the Petrograd Women's Polytechnic Institute until 1918. She nevertheless became prominent as a watercolorist in the late 1920s, during the New Objectivity (Neue Sachlichkeit) period of Estonian art, alongside her sister Natalie. Another sister, Kristine, became a sculptor. Mei married the sculptor Anton Starkopf and is occasionally cited as Lydia Mei-Starkopf.
She died in 1965 in Tallinn, the capital city.