Abdominal wall endometriosis is an uncommon clinical entity. The localization of the disease in the muscles of the abdominal wall is considered extremely rare. Our patient with two cesarean sections in her obstetric history presented to the gynecology outpatient clinic of the General Hospital of Trikala, Trikala, Greece, complaining of intense pain, particularly during menstruation, though no palpable lesions were found in the abdominal wall. The pelvic imaging revealed no abnormalities. Based on the clinical findings, endometriosis of the abdominal wall was suspected. Surgical excision of a flat lesion from the abdominal wall muscles, followed by histological examination of the surgical specimen, confirmed endometriosis of the rectus abdominis muscle. The patient's postoperative course was smooth. Six months after surgery, without additional hormonal suppressive medication, the patient reported complete relief of symptoms. To date, she is regularly followed up at the Gynecology outpatient clinic. The remarkable feature of this case is the surgical treatment of endometriosis in the rectus abdominis muscles, based on the typical clinical findings of the disease. The case emphasizes the rarity of endometriosis in the rectus abdominis muscle, the significant challenges in preoperative diagnosis, and the crucial role of recognizing typical clinical features for early diagnosis and effective treatment of abdominal wall endometriosis.