Dosage compensation is a regulatory process that balances the expression of X-chromosomal genes between males (XY) and females (XX). In Drosophila, this requires non-coding RNAs and RNA-binding proteins (RBPs) whose specific functions remain elusive. Here we show that the Drosophila RBP ​UNR promotes the targeting of the activating male-specific-lethal complex to the X-chromosome by facilitating the interaction of two crucial subunits: the RNA helicase ​MLE and the long non-coding RNA ​roX2.