Natural Resources Canada seismologist Allison Bent said it was a magnitude 4.5 quake and was centred east of the city.
"The epicentre is 21 kilometres west-northwest of Saint Hyacinthe, and that's about 37 kilometres from Montreal," Bent said in an interview from Ottawa.
There were no reports of damage, although the quake did create jitters that had some people scurrying briefly from their houses.
Laval, just north of Montreal, received 911 calls — more than 1,060 of them within 20 minutes of the tremor. Montreal had a higher than normal volume of calls as well.
"People were asking what exactly was happening. The 911 operators worked a good chunk of the night to reassure people and answer the stream of calls," Const. Simon Delorme of Montreal police said.
The temblor lasted about 10 seconds, causing buildings to rumble. But Bent said any serious damage was highly unlikely, and both the Montreal and Laval police forces said they had no reports of any.
Felt as far as Ottawa
Bent added there have been reports that a few people in the Ottawa area felt the quake.
CBC's Leah Hendry reported from Montreal that she initially thought that a truck might have gone by the three-storey walk-up where she lives with her husband.
"We both looked at each other and think: 'We lived four years in Vancouver and we experience an earthquake in Montreal,' " she said.
Hendry said she could see some lights flickering, but saw no obvious damage.
People who wrote to CBC Montreal said they felt their homes vibrating.
"I just felt the building tremble at 12:19 a.m. Was it an earthquake or something else? My roommate noticed the building shaking too. Weird," one wrote.
"Felt like an earth tremor a few minutes ago. House vibrated and noise," another said in an email.
'Very bad memories'
Dominique Anglade, a senior executive of the provincial Coalition Avenir Québec party, was one of the many people who took to Twitter to describe the quake.
A member of Montreal's large Haitian community, Anglade lost her parents in Haiti's devastating earthquake two years ago. The pair were the first Canadians confirmed dead in the disaster.
She wrote that the quake evoked "very bad memories" for her.
In Montreal's west downtown area, a couple of people briefly rushed outside as their windows shook in a four-storey apartment building near the former site of the Forum hockey arena.
Minor Montreal-area quakes common
CBC meteorologist Johanna Wagstaffe, who is also a seismologist, said the Montreal region has approximately one earthquake every five days, but most are too weak to be felt.
Before Wednesday, the most recent tremor of significant magnitude in the area was a 3.0 last Thursday located about six kilometres north of Huntingdon, a small community southwest of Montreal near the U.S. border. Three other earthquakes since Sept. 15 have been felt in Quebec, according to Natural Resources Canada.
Because the Montreal area is far from the edge of any tectonic plates, earthquakes tend to be less concentrated but can be felt over hundreds of kilometres.
Small aftershocks may be possible, Wagstaffe warned.
According to the United States Geological Survey the two most damaging earthquakes in the region happened in 1935 and 1732.
A quake with magnitude between 2 and 3 is the lowest normally perceptible to humans. A magnitude 5 quake is considered moderate.