[Background] Methamphetamine (METH) is a widely distributed addictive drug in the world. Since there is no effective treatment for METH addiction, novel therapeutic agents are required. Previously, we reported that microinjection of osteopontin (OPN), immune-modulating extracellular matrix protein, to the nucleus accumbens reduced METH preference behavior (Sci. Rep. 2017;7(1):13084) The study has offered a possibility that upregulation of osteopontin in the brain is a therapeutic strategy for the drug addiction. Here, we focused on the glatiramer acetate (GA), which is reported to increase OPN in the brain（Brain Behav. Immun. 2017;67:163-180） and examined the effects of GA on METH preference. [Methods] Mice (C57BL/6J, 8-9 weeks, male) were received subcutaneous GA (0.1 mg) administration for 14 days before and during behavioral experiments. METH (1 mg/kg) was treated to these mice during behavioral experiments. OPN-positive cells were detected in the flowcytometry experiments. [Results] GA suppressed METH-induced conditioned place preference, not hyperlocomotion. Number of OPN-positive cells increased by GA administration, and most cells were microglia. [Discussion] GA ameliorated preference behavior induced by METH, which was possibly mediated by microglial OPN upregulation. GA could be a candidate of a therapeutic agent for drug addiction.