The protests have raised troubling questions about the country's ability to provide security ahead of it playing host to some of the world's biggest events, including the 2016 Olympics in Rio.
Brazil's media has scrambled to cover the sprawling protests and has even sparked the ire of protesters, with the powerful Globo TV network in particular drawing derision.
Whenever what appears to be a Globo helicopter swoops over a demonstration, protesters hiss, raise their fists and chant slogans against what they say was the network's failure to widely show images of a violent police crackdown on protesters last week in Sao Paulo.
Such general protests are rare in this 190 million-person country, with demonstrations generally attracting small numbers of politicized participants. The latest mobilizations, by contrast, have united huge crowds.
Many protesting in Brazil's streets hail from the country's growing middle class, which government figures show has ballooned by some 40 million over the past decade amid a commodities-driven economic boom.
They say they've lost patience with endemic problems such as government corruption and inefficiency. They're also slamming Brazil's government for spending billions of dollars to host the World Cup and Olympics while leaving other needs unmet.
A November report from the government raised to $13.3 billion the projected cost of stadiums, airport renovations and other projects for the World Cup. City, state and other local governments are spending more than $12 billion on projects for the Olympics in Rio.
Attorney Agatha Rossi de Paula, who attended the latest protest in Sao Paulo along with her mother, called Brazil's fiscal priorities "an embarrassment."
"We just want what we paid in taxes back, through health care, education and transportation," said the 34-year-old. "We want the police to protect us, to help the people on the streets who have ended up with no job and no money."