The 17-year-old, a British national from Brent who cannot be named for legal reasons, has been charged with arson not endangering life.
It follows an investigation by Counter Terrorism Policing London into the attack on Saturday in Harrow.
The Metropolitan Police said the boy has been remanded in custody to appear at Westminster Magistrates' Court on Tuesday.
The charge comes after a 19-year-old man and a 17-year-old boy were arrested at separate addresses late on Sunday 19 April.
Both were arrested on suspicion of arson reckless as to whether life was endangered and were taken to a London police station.
The man has been bailed pending further enquiries.
Police said the charge relates to an alleged arson attack at around 11.35pm on Saturday at Kenton United Synagogue in Shaftsbury Avenue, Harrow.
At around midnight, officers from the Met Police who were conducting security checks at local synagogues came across what they identified as a crime scene and alerted the London Fire Brigade.
The force said that while minor damage was caused, no one was injured.
A number of Jewish sites have been targeted in separate incidents across London in recent weeks.
The Met Police have been investigating alleged attacks, which have not been linked, at the former site of a Jewish charity in Hendon on Friday, and a synagogue in Finchley on Wednesday.
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Both those incidents are near Golders Green, where four Jewish community ambulances operated by volunteer-led service Hatzola were torched in an alleged arson attack last month.
Meanwhile, on Saturday, a security incident was triggered near the Israeli embassy in central London after jars of powder, later identified as harmless, were discovered in a park.
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The Office for National Statistics (ONS) reported that the rate fell to 4.9% during the three months to February.
That was down from a previous level of 5.2%.
But the ONS said that early data from HM Revenue & Customs, covering workers in payrolled employment, showed a drop of 11,000 during March - the first month of the US-Iran war that saw global energy prices rise sharply.
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The wider figures showed average annual earnings growth, excluding bonuses, fell to 3.6% from 3.8%.
ONS director of economic statistics, Liz McKeown, said: "The number of workers on payroll remained broadly flat in recent periods, reflecting ongoing weak hiring.
"Vacancies fell to their lowest level in almost five years, but with unemployment also falling the number of vacancies per unemployed person remains broadly unchanged.
"Alongside falling unemployment, the number of people not actively seeking work increased, with data suggesting fewer students seeking work alongside their studies.
"Regular wage growth has slowed further, with growth at its lowest rate in over five years."
Recent forecasts have suggested the UK economy faces the biggest hit among developed nations due to the fossil fuel price crisis caused by the conflict in the Middle East.
The most recent study of the threat, by the respected Item Club, saw the UK's jobless rate hitting 5.8% in just over a year's time, affecting almost 250,000 people.
The higher oil and gas costs were tipped to push UK inflation to a peak of 4% this year - up from the current 3% level - with economic growth halving during 2026 to 0.7%. The report warned the economy would "flirt" with recession.
The ONS report will raise fears that the rate of inflation will soon outstrip the pace of wage rises, harming consumer spending power.
Private sector employers have long blamed surging costs, including higher national insurance contributions and minimum wage levels, for cutting staff.
The unemployment rate stood at 4.1% when Labour took office.
The government has signalled targeted, rather than universal, help ahead as the energy shock builds, though the prospects for immediate aid appear slim.
Chancellor Rachel Reeves is expected to use a statement to MPs later to claim her stewardship of the economy will help "to build a Britain that is prepared for what comes next".
She will rule out financial support that puts further upwards pressure on inflation and instead look to invest in boosting defence and energy security.
Work and Pensions Secretary, Pat McFadden, said of the ONS data: "These figures show that there was an improvement in the labour market at the beginning of the year with unemployment falling below 5%, and 332,000 more people in work than a year ago.
"But we cannot escape the effects of the war in the Middle East which are likely to feed through to prices and employment in the coming months. We will do everything we can to support the country through this period, including by slashing energy bills by up to 25% for 10,000 manufacturers.
"And we're focusing on future proofing and upskilling our workforce through our £2.5bn investment to get more young people earning and learning alongside personalised support to help sick or disabled people who had previously been written off."
Jamie Varley, 37, is accused of killing 13-month-old Preston Davey, and faces 25 further charges of sexually and physically mistreating the child.
His partner, John McGowan-Fazakerley, 32, is also accused of sexual assault, of causing or allowing the death of the child, and four other offences.
Both men, from Blackpool, deny all charges.
Preston Crown Court heard that the child was "routinely ill-treated, sexually abused, and physically assaulted" in the less than four months he spent under the couple's care.
He had been a "perfectly healthy boy" before he was adopted in April 2023, jurors were told.
But in the following months he was admitted to hospital three times, before his death on 27 July that year.
Preston was unconscious and in a state of cardiac arrest when he was brought into the Accident and Emergency Department of Blackpool Victoria Hospital by the couple.
Medics tried to revive him but he was pronounced dead less than an hour later.
He had suffered 40 traumatic injuries, including 30 external bruises, a fracture to his upper left arm, and internal bruising to his mouth and throat.
A post-mortem gave his cause of death as acute upper airways obstruction, resulting either from a smothering - most likely with a hand or soft fabric - or from the insertion of an object or objects into his mouth.
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Peter Wright KC, opening the case for the prosecution, told the jury of six women and six men: "As terrible as it is, this tragedy was not the result of some dreadful yet unforeseen accident, or natural phenomenon.
"The evidence gathered during the investigation into his untimely death revealed a much more sinister pathology."
The prosecution said Varley had sexually assaulted Preston on the day of his death, leaving him with internal injuries, while his partner was at work.
McGowan-Fazakerley was not only aware of the abuse, but participated in it too, Mr Wright said.
After Varley's arrest, police seized his phone and discovered footage recorded earlier that day showing the little boy lying on a bed with physical and obvious signs of respiratory arrest.
Varley had also taken a number of images and videos of the abuse, the court heard.
Jurors were warned to "steel themselves" before images of the baby were shown on a screen, which the prosecution said were taken after he had been sexually assaulted.
Varley, wearing a cream suit, open-necked white shirt, and shoulder-length hair with blonde streaks, sat in the dock beside McGowan-Fazakerley, who wore a green top and jeans, yards from Preston's mother in the public gallery.
Varley denies murder, manslaughter, two counts of assault by penetration, five counts of cruelty to a child, grievous bodily harm, sexual assault of a child, 13 counts of taking indecent photos or videos of a child, one of distributing an indecent photo of a child, to his co-accused, and one of making an indecent photo.
McGowan-Fazakerley denies allowing the death of a child, three counts of child cruelty, and one count of the sexual assault of a child.
The trial was adjourned until Tuesday morning.
The Metropolitan Police said the man, 40, was arrested in Coventry on Thursday on suspicion of offences under the Computer Misuse Act.
Commons Speaker Sir Lindsay Hoyle announced to parliament on Monday that the former staff member had been detained, giving a "a brief statement about a security matter".
On Tuesday, a Met spokesperson said: "A 40-year-old man was arrested at an address in Coventry by detectives from Counter Terrorism Policing London... on suspicion of offences contrary to Section One of the Computer Misuse Act 1990.
"The man, who is a former employee at the Houses of Parliament, was taken into custody before being released on bail to a date in July.
"The allegations relate to when the man was employed at Parliament."
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The spokesperson said counter-terror police were leading the investigation, aided by the Met's Parliamentary and Diplomatic Protection Command (PaDP).
The PaDP is responsible for guarding sensitive sites including the Houses of Parliament, Downing Street, and foreign embassies.
Enquiries continue.
Mr Cook, who joined the technology giant in 1998 and has been its CEO for nearly 15 years after succeeding the late Steve Jobs, will take up the role of executive chairman.
He will remain in his current role until 1 September, when Mr Ternus, the current head of the hardware engineering department, will officially take up the position.
The move comes following months of speculation that Apple was searching for a successor to Mr Cook, with Mr Ternus seen as a likely candidate to take over.
In his new role, Mr Cook will "assist with certain aspects of the company, including engaging with policymakers around the world", Apple said.
In a statement, Mr Cook said: "It has been the greatest privilege of my life to be the CEO of Apple and to have been trusted to lead such an extraordinary company.
"I love Apple with all of my being, and I am so grateful to have had the opportunity to work with a team of such ingenious, innovative, creative, and deeply caring people who have been unwavering in their dedication to enriching the lives of our customers and creating the best products and services in the world."
Mr Cook described his successor as a "visionary" with "the soul of an innovator".
He added: "He [Ternus] is without question the right person to lead Apple into the future. I could not be more confident in his abilities and his character."
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Mr Ternus joined Apple in 2001, and during his 25 years at the company has been involved in a number of its major product releases, including the iPad and AirPods, as well as several generations of iPhone, Mac, and Apple Watch.
He referred to Mr Cook as his mentor and said he was "profoundly grateful" for the opportunity to "carry Apple's mission forward".
"I am filled with optimism about what we can achieve in the years to come," he added.