The US Geological Survey (USGS) says the earthquake's epicentre was 36 kilometres north-west of Tecpan, near the Pacific resort of Acapulco in Guerrero state.
The quake, which the USGS initially rated as magnitude 7.5, struck at a relatively shallow depth of 24 kilometres.
However, the US Pacific Warning Centre says it does not expect the quake to trigger a destructive tsunami.
Buildings were evacuated in Mexico City as helicopters checked for damage overhead.
Tourists in Acapulco for Holy Week also streamed out of their hotels.
The earthquake was also felt in the eastern state of Veracruz and the southern states of Oaxaca and Chiapas.