Background Disruption of the extracellular matrix at the blood-brain barrier (BBB) underpins neuroinflammation in multiple sclerosis (MS). The degradation of extracellular matrix components, such as heparan sulfate (HS) proteoglycans, can be prevented by treatment with HS-mimetics through their ability to inhibit the enzyme heparanase. The heparanase-inhibiting ability of HS-mimetics has been investigated in various cancers but their efficacy in neuroinflammatory models like MS has not been realised. This study investigates the use of a novel HS-mimetic, Tet-29, in an animal model of MS. Methods Neuroinflammation was induced in mice by experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis. In addition, the BBB and choroid plexus were modelled in vitro using transmigration assays, and migration of immune cells in vivo and in vitro was quantified by flow cytometry. Results We found that Tet-29 significantly reduced lymphocyte accumulation in the central nervous system which, in turn, decreased disease severity in experimental autoimmune encephalomyelitis. The disease-modifying effect of Tet-29 was associated with a rescue of BBB integrity, as well as inhibition of activated lymphocyte migration across the BBB and choroid plexus in transwell models. In contrast, Tet-29 did not significantly impair in vivo or in vitro steady state-trafficking under homeostatic conditions. Conclusions Together these results suggest that Tet-29 modulates, rather than abolishes, trafficking across central nervous system barriers.