Euphemia 'Effie' Gray (1828 - 1897) was the wife of the critic John Ruskin and later of the Pre-Raphaelite painter John Everett Millais.

She was born in Perth, Scotland. Her unhappy marriage to Ruskin was annulled on the grounds of non-consummation. Despite having been married to Ruskin for several years, Effie was still a virgin and the culture had kept her sheltered enough to be a little vague about what sex was. She fell in love with Millais when he accompanied the couple on a trip to Scotland in order to paint Ruskin's portrait according to the critic's artistic principles. She modelled for his painting The Order of Release. As Millais painted Effie they fell in love. Effie left Ruskin and she filed for an annulment. In 1856, after her marriage to Ruskin was annulled, Effie and John Millais married. During the marriage she bore Millais eight children. She also modelled for a number of his works, notably "Peace Concluded".

After his marriage, Millais began to paint in a broader style, which Ruskin condemned as a 'catastrophe'. Marriage had given him a family to support (Effie and John had 8 children together) and it is claimed that Effie encouraged him to churn out popular works for financial gain and to maintain her busy social life. There is no evidence that Effie consciously pressured him. Effie's journal indicates her high regard for her husband's art. Whatever the cause Millais abandoned the Pre-Raphaelite obsession with detail after the marriage and began to paint in a looser style which produced more paintings for the time and effort. The annulment barred Effie from many social functions. She was not allowed in the presence of the queen, so if the queen was allowed to come to a party then Effie was not. Prior to the annulment, she had been socially very active and this really bothered her. Millais certainly wanted to please her and felt that he needed to maintain her at a high level. Eventually, when Millais was dying, the queen relented, allowing Effie to attend a royal function. Effie died a few months after her husband. She is buried in the Perth churchyard depicted in Millais's painting The Vale of Rest.