Palestinians in Gaza whistled and cheered as the ceasefire came into effect, while celebratory gunfire was also heard moments after 2am on Friday.
In East Jerusalem's Sheikh Jarrah neighbourhood, a focal point of Palestinian protests in recent weeks, drivers honked car horns to mark the moment.
Israel and Gaza rulers Hamas on Thursday committed to a ceasefire to go into force within hours, aimed at ending 11 days of deadly cross-border fire.
The deal brokered by Egypt was announced by the office of Israeli Prime Minister Benjamin Netanyahu after a meeting of security officials.
The security cabinet "unanimously accepted the recommendation of all of the security officials ... to accept the Egyptian initiative for a mutual ceasefire without pre-conditions", Mr Netanyahu's office said.
Abu Obida, the spokesman for Hamas's armed wing, said the group had prepared to launch rockets into Israel before the deal was reached.
"But we agreed to the ceasefire and we will watch the behaviour of the enemy until 2am," when the ceasefire is expected to come into effect, Abu Obida said.
Shortly after the announcement was made, Israeli sirens warned of incoming fire from Gaza.
A journalist for The National in Gaza City said Israeli shelling was continuing.
"The reality on the ground will determine how we move forward," Israeli Defence Minister Benny Gantz said.
The conflict broke out on May 10 when Hamas fired rockets towards Jerusalem, after weeks of violence in the ancient city left hundreds of Palestinians wounded.
Israeli police were accused of heavy-handed tactics across occupied East Jerusalem, particularly in Al Aqsa Mosque compound, which is the third-holiest site in Islam.
Tension was further inflamed by eviction orders hanging over Palestinian families in the Sheikh Jarrah neighbourhood in East Jerusalem, as well as police banning people from gathering at the Old City's Damascus Gate during Ramadan.
After rockets were fired towards Gaza, Israel launched a blistering attack on the enclave.
The country's military struck hundreds of targets it says were Hamas infrastructure, including a tunnel network.
Hamas and other militant groups in residential areas fired more than 4,000 rockets, according to the Israeli military, although hundreds fell short and most of the rest were intercepted.
At least 232 Gazans were killed, including 65 children, with 1,710 people wounded, the Gaza Health Ministry said.
Two children were among 10 people killed in Israel by rocket fire, while 118 were wounded, the Magen David Adom emergency services said.
Since the fighting began, Gaza’s infrastructure, already weakened by a 14-year blockade, has rapidly deteriorated.
Medical supplies and fuel for electricity are running low in the territory, which was put under a blockade by Israel and Egypt after Hamas seized power in 2007.
Israeli bombing damaged more than 50 schools across the territory, according to advocacy group Save the Children, completely destroying at least six.
About 91,000 Gazans fled their homes, two thirds of whom sought shelter in schools, the UN said.
Israeli attacks also damaged at least 18 hospitals and clinics and destroyed one, the World Health Organisation said.
