The volcano created a fountain of lava that rose 2,600 feet above the summit crater.
A much taller plume of ash was visible from many parts of the country, including the capital of Guatemala City.
Pacaya is one of Central America’s most active volcanoes, striking a picturesque pose on the horizon just to the south of the capital.
Debris from a 2010 eruption killed three people, injured 59 others and destroyed about 100 homes.
This January, a river of lava nearly 2,000 feet wide and 2 miles long flowing down its flanks prompted some nearby residents to flee their homes.
Guatemala has four active volcanoes that have caused catastrophic damage in the past.
The explosive eruption of Santa Maria in 1902 was one of the world's largest eruptions of the 20th century.
Photo: National Disaster Management Center (Conred)