Trehalose is a disaccharide produced by many organisms to better enable them to survive environmental stresses, including heat, cold, desiccation, and reactive oxygen species. Mammalian cells do not naturally biosynthesize trehalose; however, when introduced into mammalian cells, trehalose provides protection from damage associated with freezing and drying. One of the major difficulties in using trehalose as a cellular protectant for mammalian cells is the delivery of this disaccharide into the intracellular environment; mammalian cell membranes are impermeable to the hydrophilic sugar trehalose. A panel of cell-permeable trehalose analogues, in which the hydrophilic hydroxyl groups of trehalose are masked as esters, have been synthesized and the ability of these analogues to load trehalose into mammalian cells has been evaluated. Two of these analogues deliver millimolar concentrations of free trehalose into a variety of mammalian cells. Critically, Jurkat cells incubated with these analogues show improved survival after heat shock, relative to untreated Jurkat cells. The method reported herein thus paves the way for the use of esterified analogues of trehalose as a facile means to deliver high concentrations of trehalose into mammalian cells for use as a cellular protectant.