Henri Ernest Ponthier de Chamaillard, usually known as Ernest de Chamaillard, (9 December 1862, Gourlizon – 1931, Eaubonne) was a French artist, one of a group of painters who gathered in the Breton village of Pont-Aven.
As his real interest was painting, in June 1888 he went to Pont-Aven where he met Paul Gauguin.
He quickly adopted Gauguin's Impressionism, joining the other painters in the group including Charles Laval, Émile Bernard and Henry Moret.
He exhibited his work at the Bernheim-Jeune gallery in 1906 and 1910 with catalogue prefaces by Arsène Alexandre.
He experienced material difficulties during the First World War, worsened by the deaths of his two sons.