The service included readings by veterans and political leaders, musical performances and re-enactments from D-Day.
World leaders including Donald Trump, the Queen, Angela Merkel and Theresa May were in the royal box to watch the event.
Here are some of the best pictures from the service.
2. D-Day 75
Britain's Queen Elizabeth II attends an event to commemorate the 75th anniversary of the D-Day landings, in Portsmouth. Picture: JACK HILL/AFP/Getty Images
Photo: JACK HILL
3. D-Day 75
Veterans gather on stage at the D-Day 75 Commemorations on June 5, 2019 in Portsmouth. Picture: Chris Jackson-WPA Pool/Getty Images
Photo: Chris Jackson
4. D-Day 75
Performers dressed as soldiers perform during an event to commemorate the 75th anniversary of the D-Day landings, in Portsmouth. Picture: DANIEL LEAL-OLIVAS/AFP/Getty Images
Photo: DANIEL LEAL-OLIVAS