Fragile X syndrome is the most common heritable form of intellectual disabilities and a leading genetic cause of autism, caused by mutation of the gene encoding FMRP. Researchers have not found an effective treatment for the cognitive and social interaction deficits associated with fragile X. The mammalian target of rapamycin (mTOR) is a central regulator of cell growth, proliferation, survival, translation and the actin cytoskeleton. mTOR is a kinase that integrates external cues and forms two distinct complexes, mTOR Complex 1 (mTORC1) and Complex 2 (mTORC2), which have distinct functions and downstream targets. Whereas mTORC1 is a central regulator of cap-dependent translation, mTORC2 is a pivotal regulator of the actin cytoskeleton, spine structure and memory. Dysregulation of mTORC1 in fragile X syndrome is well established, but a role for mTORC2 is still unclear.