Spatial and temporal control of mRNA expression is essential for establishing cell polarity. Endosomes are linked to subcellular mRNA localization and translational control, yet little is known about the mechanism of RNA localization to endosomes. Using Xenopus egg extracts we found that the endosomal-sorting complex, ESCRT-II, bound to hundreds of mRNAs, including many mRNAs previously identified to localize asymmetrically in oocytes. Further characterization of the ESCRT-II:RNA interaction revealed that ESCRT-II is an RNA binding protein that shows length but not sequence specificity for RNA. Characterization of ESCRT-II in extract revealed that ESCRT-II is in an mRNP complex with the RNA binding protein Vera and the microtubule motor protein, Dynein, suggesting that other factors may regulate which mRNAs associate with in extract. In addition to RNA, ESCRT-II bound to membranes containing PtdIns(3)P phospholipids, the main phospholipid of endosomes. Interestingly, ESCRT-II simultaneously bound directly to RNA and membranes and was sufficient to tether RNA to specific phospholipids. Furthermore, immunodepletion of ESCRT-II from egg extract abolished mRNA localization to endosomes. Additionally, we show some evidence to suggest that ESCRT-II is involved in both the spatial and temporal control of mRNA during Xenopus oogenesis. Together these data demonstrate that ESCRT-II is both necessary and sufficient for mRNA localization to endosomes, and that this interaction is likely crucial for the spatial and temporal control of mRNA during Xenopus development.