It happened in Drapers Court, Wellington, shortly after 9pm on Monday.
Firefighters from Wellington were called to the scene and used breathing apparatus, a hose reel jet and thermal imaging camera to deal with the fire.
Laura Maltby, spokesman for West Mercia Police, said: "Police were called following a report a car was alight. No injuries were reported.
"Investigations into the fire are currently ongoing and officers are keeping are open mind as to the cause but it is believed it may have been started deliberately.
"Officers would like to speak to anyone who witnessed the incident or who saw anyone acting suspiciously in the area at the time."
Anyone with information is asked to call West Mercia Police on 101 quoting incident number 821S of September 4. Alternatively, contact Crimestoppers anonymously on 0800 555111 or at crimestoppers-uk.org