The 71-year-old took the oath of office in a ceremony in the Kremlin, with several thousand people including senior Russian politicians and other high-ranking guests in attendance.
Putin received 87% of the vote in March’s presidential election, which was overshadowed by widespread allegations of fraud, coercion and irregularities. He faced no credible opposition after his main challenger was barred from running.
Live coverage of the inauguration on Russian television showed Putin being driven to the Grand Kremlin Palace in a Russian-made Aurus limousine before observing a parade by the Kremlin Regiment.
He then swore a oath to protect the rights of Russia's citizens and to defend its constitution.
Putin, who has dominated Russian politics for a quarter of a century, was only allowed to run for re-election again as a result of constitutional changes he pushed through in 2020. His new six-year term will run until 2030, when he will be 77 years old.
In a speech after the ceremony, Putin said his re-election proved Russian citizens believed in his leadership and supported his policies, including the invasion of Ukraine he launched more than two years ago.
Putin said "Russia is not refusing dialogue with the West" but stated that the country would choose its own path, including in Ukraine. He asserted his confidence that Russia would defeat Ukraine, saying, "We will win."
Kremlin spokesman, Dmitry Peskov, said Putin would present his candidate for prime minister on Tuesday. The current Prime Minister Mikhail Mishustin is expected to retain his position, but political observers are waiting to see whether 74-year-old Foreign Minister, Sergei Lavrov, will be reappointed after 20 years in the post.
There is also considerable speculation about the future of Defence Minister, Sergei Shoigu, whose top deputy, Timur Ivanov, was recently arrested on corruption charges.
According to information from Russia's parliament, the Duma, lawmakers could approve new ministry appointments by May 15.