The crowd gathered in Wenceslas Square in central Prague called on the government to do more to control rising energy prices while criticizing the EU and NATO.
Some of the groups represented at the demonstration were the large populist anti-migrant party "Freedom and Direct Democracy" and the Communist Party.
Organizers said the Czech Republic should be militarily neutral and secure direct contracts with gas suppliers, including Russia.
- The purpose of our demonstration is to demand change, mainly to solve the issue of energy prices, especially electricity and gas, which will destroy our economy this fall, co-organizer Jiri Havel told Czech media.
Distrust from the opposition
The protest was held a day after the government survived a no-confidence vote following opposition claims of government inaction on inflation and energy prices.
Prime Minister Petr Fiala, who leads the centre-right in the country's five-party alliance, believes that the protesters do not want the best for the country.