Emergency services were called to junction 4 of the motorway in Bebington at about 7.10pm on Sunday to a report that a woman in her 70s had fallen from a bridge.
She was taken by ambulance to hospital but later died from her injuries. There are not believed to be any suspicious circumstances surrounding her death.
A Merseyside Police spokesman said: “A post mortem examination will be carried out in due course, although, at this stage, there are not believed to be any suspicious circumstances surrounding her death. Next of kin are in the process of being informed. An investigation into the full circumstances surrounding the incident is continuing.”
The northbound carriageway of the M53 was closed at junction 4 following the incident but reopened at just after 9pm.
Anyone who may have witnessed the incident is asked to call Merseyside Police on 101.