California Governor Jerry Brown has signed several gun control bills into law, including one measure that raises the minimum age for buying rifles and shotguns from 18 to 21.
Another law will prohibit Californians with previous convictions for domestic violence charges and those who have been hospitalized for mental health issues more than once in one year from making firearm purchases.
The new laws come seven months after a gunman opened fire with a semiautomatic assault-style rifle at Marjory Stoneman Douglas High School in Parkland, Florida, killing 14 students and three adults, the second-deadliest mass shooting at a public school in U.S. history.
The rampage, which authorities say was carried out by a former student who was 19, has spurred unprecedented activism by victims and their families to prevent future gun violence and demanding stricter gun control across the United States.
California already has some of the strictest gun laws in the nation. The new laws, which go into effect Jan. 1, exempt law enforcement officers and military service members.
Federal law already prohibits people younger than 21 from buying a handgun from a licensed firearms dealer.
Brown also signed a bill that makes it easier for family members and police to take firearms and ammunition away from people who are believed to be a threat to commit violence.
The Law Center to Prevent Gun Violence in its annual scorecard last year gave California an A-, and said it has the strongest laws in the nation.