Mucinous ovarian neoplasms associated with teratomas (MOvNTs) are uncommon with only a few large series published thus far [[1], [2], [3]]. Reports have shown that they occur in 2% to 11% of ovarian mature cystic teratomas [[1], [2], [3]]. The origin of MOvNTS can be either independent of the teratoma with Mullerian-type phenotype or be derived from the germ cell components of the tumor and in such cases typically have intestinal/appendiceal-type phenotype. Non-teratoma associated primary mucinous tumors are more frequently of Mullerian/surface epithelial origin and are morphologically and immunophenotypically different from the appendiceal-like mucinous neoplasms that may be encountered in teratomas [1,3,4]. Additionally, MOvNTs are associated with pseudomyxoma ovarii and peritonei, features that are more commonly seen in metastatic tumors involving the ovary [1,[3], [4], [5], [6], [7], [8], [9], [10], [11]]. Histologically, MOvNTs are a heterogeneous group of tumors; and range from cystadenoma to borderline tumor and carcinoma, as traditionally classified [[1], [2], [3]]. However, one of the objectives of the 2020 WHO Classification of The Female Genital Tumors has been to introduce terminology harmonization for tumors that share similar histological features, but occur in different anatomical sites [12]. While not explicitly stated, there is a tacit suggestion to apply such a terminology change to appendiceal-type mucinous neoplasms arising in mature cystic teratomas [12]. This may result in challenges with classification, as appendiceal mucinous tumor nomenclature i.e. low grade appendiceal neoplasm (LAMN) and high grade appendiceal mucinous neoplasm (HAMN) is not reliably reproducible even among gastrointestinal (GI) pathologists [[13], [14], [15]]; and pathologists lack experience in applying such terminology to ovarian tumors. Herein, we present the clinicopathological features of a cohort of fifty cases of MOvNT with particular attention to the histologic appearance of the tumors, i.e. Mullerian/surface epithelial versus appendiceal-like, and the application of the suggested appendiceal mucinous neoplasm nomenclature for the latter.