The Groucho/TLE family of conserved WD40 domain-containing transcriptional co-repressors are important regulators of development in many species. Several short Groucho-like proteins that lack the C-terminal WD40 domains also exist and can act in vitro as antagonists or agonists of Groucho/TLE proteins. But what is their in-vivo function? On p. 1799, Oliver Hobert and co-workers report that, in C. elegans, the novel, short Groucho-like protein LSY-22 promotes the function of the Groucho orthologue UNC-37. In a screen for genes that control a left/right asymmetric cell fate decision in the C. elegans nervous system, the researchers isolated loss-of-function alleles in two distinct loci that cause identical changes in neuronal fate specification and in several other developmental processes. These loci encode UNC-37, the C. elegans orthologue of Drosophila Groucho, and a short Groucho-like protein, LSY-22, which, the researchers show, physically interact in vivo. These results suggest that, instead of antagonising Groucho functions as previously proposed, short Groucho-like proteins may instead promote Groucho functions.