Serious adverse reactions following immunisation with adult tick-borne encephalitis (TBE) vaccines are rare, but when they occur, they most frequently involve the nervous system. We present a case of a female patient who developed a sensory and motor L4 monoradiculopathy following self-injection of an inactivated vaccine against TBE in the ipsilateral quadriceps muscle. The motor and sensory L4 dysfunction vanished after 12 months. TBE vaccine-induced radiculopathy should be considered as a mimic of spinal root compression.