Police said they had found three children alive at the scene but all 11 adults at the party had been shot dead.
It had taken place in a tent set up by the host outside their home in a residential area of the city.
Mexico has recently seen a surge in violence linked to disputes between drug cartels.
In May alone, 2,186 killings were recorded - approximately 70 a day.
A recent trend has seen hit men murdering whole families, including children.
Masked men burst into a children's birthday party in the Mexican city of Tizayuca in central Hidalgo state, killing 11.