Kim Gaucher of Mission, B.C., led Canada with 17 points and Nirra Fields of Montreal added 15 points. Canada will play Australia on Friday.
Canada jumped out to an early lead against the Czechs and kept the pressure on throughout the game. Canada led 22-13 after the first quarter and 44-32 at the half before pulling away in the fourth quarter.
"Our speed negates their size," Canadian head coach Lisa Thomaidis said on a conference call. "We really had advantages all over the floor with our speed and you could see it really was what (helped us) dominate at the offensive end tonight."
Later Wednesday, France will play Brazil, Belarus will take on China and Serbia meets Cuba.
Canada finished third in its group phase after posting a win over Mozambique and losses to Turkey and France. The Czechs, meanwhile, posted comfortable wins over Brazil and Japan before falling to Spain.
It was an impressive bounceback performance from the Canadians after a tough four-point loss to France a day earlier.
"We're ecstatic to get to the top eight, the last time we got there was 1994," Thomaidis said. "As happy as we are with this win, we're carrying on with business as usual and moving on. We've got a tough opponent in two days and we've got to see what we can do here.
"These opportunities don't roll around very often. We had a great win at the perfect time but we've got to keep this thing rolling because we seem to be getting better each game."
Australia, the United States, Spain and host Turkey all earned direct quarter-final berths after posting unbeaten records in the group phase.
Japan, Angola, Mozambique and Korea were eliminated after going winless in pool play.
The other quarter-final games were also scheduled for Friday. The semifinals were set for Saturday and the championship game was scheduled for Sunday.
The Czechs reached the final of the 2010 world championship before falling to the United States. Canada finished 12th at that tournament.
Canada is making its third consecutive women's world championship appearance.