A Metropolitan Police statement said officers on deterrence and reassurance patrols "noticed damage to a window" of the Kenton United Synagogue at around midnight.
"On further inspection they saw smoke inside a room and evidence that a bottle with some sort of accelerant had been thrown through the window," the statement continued.
The force said the incident is being treated as arson.
A Campaign Against Antisemitism spokesperson said: "Last night, another Jewish synagogue in London was firebombed, this time in Kenton. Thankfully, the damage was limited."
A spokesperson for the Community Security Trust (CST) said the attack caused "minor smoke damage to an internal room, but there were no injuries and no significant structural damage".
The UK's Chief Rabbi, Sir Ephraim Mirvis, has called the attack "cowardly" and said "a sustained campaign of violence and intimidation against the Jewish community of the UK is gathering momentum".
The synagogue is close to a school and a children's playground. By Sunday morning, the area was under a large police cordon, with forensics officers, fire investigation dogs and plainclothes officers at the scene.
It comes a day after an arson attack on a building that used to house a Jewish charity elsewhere in northwest London, which is also being investigated as an antisemitic hate crime.
London Mayor Sadiq Khan said the Metropolitan Police have "stepped up resources" in the area.
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"There is no place for antisemitism in our city, and the perpetrators of these despicable attacks will face the full force of the law," he wrote in a post on X. "London will always stand united against those seeking to divide us."
Sir Keir Starmer said he was "appalled by recent attempted antisemitic arson attacks in North London" in a social media post.
"This is abhorrent and it will not be tolerated," the prime minister said. "Attacks on our Jewish community are attacks on Britain."
A building that used to belong to a Jewish charity in Hendon, northwest London, was attacked on Friday by a man who lit a plastic bag at the entrance before fleeing.
While Jewish Futures no longer uses the site, the signage still bears its name.
Police are also treating that attack as an antisemitic hate crime and no arrests have been made.
On Friday, suspicious items - including two jars containing powder - were found near the Israeli embassy in west London.
Police said the embassy was not attacked but officers are still investigating whether the items are connected to a video posted by an Iran-linked Islamist group, which claimed to have targeted the building with drones carrying dangerous substances.
The incidents followed a spate of other attacks in recent weeks. Last month, four ambulances run by a Jewish charity were burned down in Golders Green, north London, leading to four arrests.
Two people were also arrested this week after bottles of petrol were thrown at a synagogue in Finchley, northwest London.
It comes after he reportedly failed to pay nearly £100,000 in corporation tax.
Mr Tice did not pay any tax on the profits he made from four shell companies between 2020 and 2022, The Sunday Times has reported.
The companies were set up to receive dividends from his property investment firm and pass the money to their parent company, the newspaper said.
It said Tisun Investments Ltd then transferred £1,113,000 to Reform UK between March 2020 and May 2022.
In a statement on X, Mr Tice said his "long career with multiple businesses" meant his accounting was "bound to feature some errors".
He said: "In a highly successful career spanning 40 years, I have done business in 12 countries across three continents, and been a director of more than 150 companies.
"I have helped build thousands of homes, creating thousands of jobs and generating hundreds of millions of value for shareholders and investors along with many tens of millions of tax for HMRC.
"I am very proud of this record. Throughout this career I have taken professional tax advice and have always paid everything that I was advised to pay.
"Here's the reality: tax efficiency is a basic corporate responsibility and duty to shareholders. A long career with multiple businesses is bound to feature some errors.
"Naturally, I am always happy to put things right and if numbers need rechecking, of course, I will pay what is owed - be that more or less."
Dan Neidle, founder of Tax Policy Associates, wrote on X that "around £98k of corporation tax is due", plus "about £27k of interest".
Reform's Treasury spokesperson Robert Jenrick said on Sunday morning that Mr Tice "thinks he may have overpaid tax because he paid it through his personal taxation, rather than through the company".
He told the BBC's Sunday With Laura Kuenssberg programme: "If it transpires that he's underpaid tax, of course he'll settle it. But that is not his position. He thinks he's paid the right tax, and that's absolutely right.
"As far as I know, HMRC are not investigating. So there is no story."
Reform UK last week said any oversight on Mr Tice's part was "a minor administrative error".
The Boston and Skegness MP received at least £91,000 because his property investment company, Quidnet REIT Limited, did not pay the required 20% tax on the dividends before they were issued to him and his offshore trust in Jersey, The Sunday Times reported.
Mr Tice said on X that "overall HMRC received the correct amount of tax due" and that any issue was due to "complex tax technicality around dividends to certain shareholder classes in REITs".
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Labour Party chair Anna Turley said: "Richard Tice's credibility is in tatters and Nigel Farage needs to urgently explain why he remains Reform's deputy leader.
"This is a major scandal that's not going away. Tice has called for others to resign over tax errors that involved less money than this."
Grant McKinnon, 30, was last seen in Cardowan Road, Glasgow, at 4am on Saturday morning - the same time police were called to the "suspicious" death of a woman in the area.
Police Scotland have not confirmed if the two incidents are linked.
Anyone who has seen Mr McKinnon has been told not to approach him and instead to call 999 immediately.
He is 6ft tall and was last seen wearing a black jacket with a red hood and blue jeans.
Detective Superintendent Gary Ferguson said: "Grant is considered to be dangerous and I'm appealing for information from the public to help us trace him as soon as possible.
"If anyone sees Grant, they should not approach him but contact police immediately.
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Earlier, Police Scotland said the death of a woman who was injured in Cardowan Road was being treated as "suspicious".
The woman was pronounced dead at the scene and detectives launched an investigation.
Anyone with information should call 999 quoting reference 0523 of 18 April, or can contact Crimestoppers anonymously on 0800 555 111.
Juha Miettinen, 66, died after a crash involving seven cars at the Nurburgring Nordschleife circuit in Germany on Saturday.
Six other drivers were taken to the medical centre and nearby hospitals for precautionary examinations but none are in a life-threatening condition.
"Following the collision between several vehicles, race control immediately halted the race to allow for extensive recovery and rescue operations," organisers said in statement.
"Despite the immediate arrival of emergency services, the emergency medics were unable to save the driver involved, Juha Miettinen, after he had been extracted from the vehicle."
Miettinen died in the circuit's medical centre despite several attempts to resuscitate him, the statement added.
Verstappen was using the weekend's races to prepare for his first 24-hour race at the historic circuit on 16 and 17 May.
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"Shocked by what happened today," he posted on social media.
"Motorsport is something we all love, but in times like this it is a reminder of how dangerous it can be.
"Sending my heartfelt condolences to Juha's family and loved ones."
A minute's silence will be held in memory of Miettinen during the grid formation for Sunday's race.
Running nearly 13 miles through wooded German hills, with more than 150 corners and barriers often close to the track, the Nordschleife layout at the Nürburgring is known for high-risk thrills.
F1 has not used it since 1976, when then-reigning champion Niki Lauda suffered severe burns in a crash.
Ben Roberts-Smith, 47, released on bail this week, is charged with five counts of war crimes over the alleged murder of five unarmed Afghan civilians in Uruzgan province, in the country's south, between 2009 and 2012.
He is accused of shooting two victims dead and allegedly ordered subordinates to shoot the other three victims.
Each charge carries a maximum sentence of life in prison.
The former Special Air Service (SAS) corporal, who was arrested on 7 April, has consistently denied accusations of wrongdoing, many of which were first reported by Nine Entertainment newspapers in a series of articles from 2018 onwards.
Opposing bail, prosecutor Simon Buchen described the charges against Roberts-Smith as "among the most serious known to the criminal law".
Speaking to the media on Queensland's Gold Coast, the former soldier said he was always within the rules of engagement in Afghanistan.
"I categorically deny all of these allegations, and while I would have preferred these charges not be brought, I will be taking this opportunity to finally clear my name," he said.
"I'm proud of my service in Afghanistan."
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After more than a week in custody, Roberts-Smith was granted bail after a judge said the case would probably take years to reach court.
Prosecutors had opposed bail over concerns he might attempt to contact witnesses.
Police have said they will allege Roberts-Smith's victims were not active in hostilities at the time of their deaths and were detained, unarmed and under the control of Australian troops when killed.
He lost a defamation suit over the media accusations in 2023 and was found, on the balance of probabilities, to have been involved in the murder of four Afghan civilians.
At that trial, Roberts-Smith testified he had never killed an unarmed Afghan and said he had never committed a war crime. He claimed he was the victim of spiteful fellow soldiers' lies and that others were jealous of his medals.
Roberts-Smith was awarded both the Victoria Cross and Medal of Gallantry for his service in Afghanistan and is only the second Australian veteran of the Afghanistan campaign to be charged with a war crime.
Defence lawyer Slade Howell told the bail hearing the case "may properly be described as exceptional in the sense that it is out of the ordinary".
"The use of domestic courts to prosecute alleged war crimes committed by a highly decorated Australian soldier deployed overseas repeatedly by the Australian government to fight a war on its behalf is unprecedented and is uncharted legal territory of the common law of this country," Mr Howell said.