Evening primrose soap is a type of soap that contains evening primrose oil as one of its main ingredients. Evening primrose oil is derived from the seeds of the evening primrose plant (Oenothera biennis) and is rich in essential fatty acids, particularly gamma-linolenic acid (GLA).

Evening primrose oil is believed to have various potential benefits for the skin, including moisturizing properties and anti-inflammatory effects. Some people use evening primrose soap to help alleviate symptoms of conditions such as eczema, psoriasis, acne, and dry skin.