子宫内膜炎（英语：Endometritis）是指发生于子宫内膜的炎症。子宫内膜炎分为急性与慢性两种，临床以前者较为常见，后者少见。急性子宫内膜炎是在子宫内膜腺体上有微脓肿或嗜中性粒细胞呈现；慢性子宫内膜炎则是子宫内膜基质上出现大量浆细胞。子宫内膜炎的主要病因是感染。子宫内膜一般有较强的自然保护作用和抗炎能力，但一旦遭受破坏，则容易发病且直接波及子宫肌层，并延伸至宫旁组织。症状包括有下腹疼痛、发烧、不规则阴道出血及分泌物。医师通常采取广谱抗生素进行治疗。

医学术语子宫肌内膜炎（endomyometritis）有时是指一类特殊的子宫内膜和子宫肌层的炎症。

Endometritis is inflammation of the endometrium, the inner lining of the uterus.

Pathologists have traditionally classified endometritis as either acute or chronic: acute endometritis is characterized by the presence of microabscesses or neutrophils within the endometrial glands, while chronic endometritis is distinguished by variable numbers of plasma cells within the endometrial stroma. The most common cause of endometritis is infection. Symptoms include lower abdominal pain, fever and abnormal vaginal bleeding or discharge. Caesarean section, prolonged rupture of membranes and long labor with multiple vaginal examinations are important risk factors. Treatment is usually with broad-spectrum antibiotics.