Thousands of Israelis gathered in Tel Aviv on Saturday to protest legislative moves to limit the Supreme Court's power and to grant Prime Minister Benjamin Netanyahu immunity from prosecution.
The protest was organised and attended by all the country's opposition parties.
The opposition parties claim that Netanyahu is making moves to protect himself from corruption cases.
Netanyahu faces three corruption cases related to fraud and bribery. He denies all wrong-doing and has called the charges a "witch hunt."
Netanyahu won a fifth term in office in April and is trying to form a right-wing coalition government before Wednesday.
Benny Gantz, who ran against Netanyahu in April, attended the protests and tweeted that they were "powerful" and "opened an important week for the future of Israel."
National Israeli media said it was a rare show of unity for the opposition parties, all while Netanyahu has struggled to form a coalition of right-wing parties.
Protesters reportedly compared Netanyahu to Turkish President Recep Tayyip Erdogan by wearing Ottoman-style hats and carrying portraits of Erdogan.
The police did not release official figures for how many protesters attended.