We describe a case of a 15-year-old male presenting with an unusual right-sided paratesticular mass in whom the diagnosis of an ovarian-like paratesticular müllerian-type papillary serous tumor was made. The tumor, also referred to as serous papillary cystadenoma by some authors, depicted papillae with fibro-vascular cores lined by a bland pseudostratified ciliated epithelium. The immunohistochemistry showed the tumor to have diffuse reactivity against BerEp4, epithelial membrane antigen, and progesterone receptor; focal reactivity against cytokeratins AE1/AE3, cytokeratin 7 (CK7), Ca125, estrogen, and carcinoembryonic antigen; and negative reactivity for calretinin, Wilms tumor 1 (WT1), and CK20. Surgical management involved resection of the tumor followed by regular follow-up. Paratesticular müllerian-type papillary serous tumor is an infrequent lesion that has seldom been described in the pediatric-age patient. To our knowledge, whereas only 2 cases of serous papillary borderline malignancy have been previously described in this age group, this is the 1st time a serous papillary tumor is reported in a child. The pediatric surgeon, the clinicians, and the pathologist should be aware of this entity, as a conservative management would be preferable.