Thousands had been expected to attend the event in central London as part of the Campaign Against Antisemitism (CAA) event, which would have coincided with today's pro-Palestinian march.
The CAA said it cancelled the event, where people would have walked "where they please", after receiving "numerous threats" and identifying "hostile actors (who) seem to have intended to come to any meeting locations that we announced".
It added: "The risk to the safety of those who wished to walk openly as Jews in London... as part of this initiative has therefore become too great.
"We are no less angry about these marches than our Jewish community and its allies. We want to walk."
The CAA said it had suggested "concrete measures" to government aimed at changing how the pro-Palestinian protests are policed.
It highlighted concerns over antisemitic chants, inflammatory placards, and instances of glorifying terrorism, as well as incidents of violence, including attacks on police officers.
"Police have told us that they intend to handle the march no differently from the passive way that they have become accustomed to over the course of more than six months," the group added.
But the Met's assistant commissioner, Matt Twist, said the force aimed to police "without fear or favour", adding that the impact of the weekly pro-Palestinian protests was "felt widely" but had been a "particular cause of fear and uncertainty in Jewish communities".
Mr Twist added that pro-Palestinian protests had "never" reached the threshold where it was a "risk of serious public disorder".
He said: "The only legal route to ban a march is if there is a risk of serious public disorder - that is rioting or serious violence that could not be dealt with by other restrictions or conditions.
"We have never got close to that threshold on these Palestinian Solidarity Campaign (PSC) marches to date."
The CAA had announced its Walk Together after its chief executive, Gideon Falter, was prevented from crossing a road near a pro-Palestinian protest by a police officer last week because he was "openly Jewish".
Footage showed a tense, lengthy stand-off between police and Mr Falter as one Met officer described his presence as "antagonising".
The campaigner then spoke to another officer who said if he remained in the area, he would be arrested.
After the incident, Mr Falter was critical of the Met and said there were "no-go zones for Jews", while Scotland Yard apologised twice for the officer's choice of words.
The PSC protest today, which organisers claim could attract "hundreds of thousands" of protesters, will take place on a pre-agreed route.
Simultaneously, a separate demonstration arranged by the pro-Israel Enough is Enough group will go ahead following a route parallel to the PSC march.
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The Met Police said 450 arrests have been made since the pro-Palestinian marches began, with 193 of those being for antisemitic offences, the majority involving placards, chanting or expressions of hate speech.
The cost of policing the protests stands at approximately £38.5m, the Met added.

The monarch has been receiving outpatient care since early February and despite the good news, palace sources stressed His Majesty is still continuing treatment.
The announcement that the King is doing well will be a morale boost for the family, with both him and the Princess of Wales being diagnosed with cancer.
A Buckingham Palace spokesperson said: "His Majesty's medical team are very encouraged by the progress made so far and remain positive about the King's continued recovery."
They added: "His Majesty's treatment programme will continue, but doctors are sufficiently pleased with the progress made so far that the King is now able to resume a number of public-facing duties."
The palace also released a new photograph of the King and Queen, taken in Buckingham Palace on 10 April, the day after their 19th wedding anniversary.
To mark his full return, Buckingham Palace said the royal couple will visit a cancer treatment centre on Tuesday.
"This visit will be the first in a number of external engagements His Majesty will undertake in the weeks ahead," the palace said.
"In addition, The King and Queen will host Their Majesties The Emperor and Empress of Japan for a state visit in June."
The King and Queen are to celebrate the first anniversary of their coronation on 6 May.
The palace said: "Their Majesties remain deeply grateful for the many kindnesses and good wishes they have received from around the world throughout the joys and challenges of the past year."
The prime minister has welcomed the news, posting on X: "Brilliant news to end the week!"
The monarch has, by all accounts, been keen to get back to work and has recently been seen greeting members of the public at Easter and meeting the governor of the Bank of England to unveil new banknotes.
Sky News royal commentator Alastair Bruce said: "I think with all the guidance that the doctors have given, the King has been able to make this announcement now, and it means that the palace can start to make a proper plan for the King's events for the summer and allow him to really put his back into his role.
"Hopefully that steady progress will continue.
"The important point is the palace can draw him back from certain events and maybe alter how they will carry them out.
"The King is looking forward to this and especially the arrival of the Emperor and Empress of Japan later in the year, which is key business for Britain.
"I think he will be much cheered by being given this partial go-ahead."
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Consultant oncologist Dr Karol Sikora told Sky News his return to public duties "is very good news".
"The recommendation that he at least resumes partial duties is excellent. It means that the cancer is under control," he said.
"The type of cancer and the treatment he's had has not been disclosed. That doesn't matter. He's going back to work which means things are going in the right direction.
"I think the outcome will be great."
The King's diary will not be a full summer programme, and attendance will be announced nearer the time and "subject to doctors' advice", with "adaptations made where necessary to minimise risks".
The warmer weather in the approach to summer will allow events to be held outside and minimise the risk posed by other people that many cancer patients face.
The spokesperson added: "The pacing of the King's programme will be carefully calibrated as his recovery continues, in close consultation with his medical team."

Sonny Suberu, 60, was found dead in the Cambodian capital of Phnom Penh following a fall from the 22nd floor of his hotel on 26 March.
The retired IT consultant and author from London was on a solo trip through South Asia and had travelled the world extensively.
Cambodian authorities say Mr Suberu's death was suicide but his daughter Shannon doesn't believe the police account - and points out another man fell to his death at the same hotel a few weeks before her father arrived.
She told Sky News: "[The Cambodian authorities] are saying he's fallen from a roof. In the photos that I've received of my dad, there's not a bruise to his face.
"He looks in pristine condition. So to me, it just makes no sense. If you're telling me you're falling from a 22-floor building, your body is going to be unrecognisable.
"They've literally provided no evidence. There's no CCTV.
"Right now we don't even know where his stuff is. The hotel staff are saying the police have it, the police are saying the hotel staff have it."
When asked if the Foreign Office is doing enough to answer her questions about the circumstances that led to her father's death, Shannon said: "I don't believe so.
"My dad was a UK national. He was born and raised here. The fact that you have turned around and basically said to me the UK Cambodian authorities suspect no foul play - so there's literally absolutely nothing that they can do on our behalf? It's mad.
"How did he fall? Did he fall off the balcony? If he did fall off the balcony, what was wrong with the balcony?"
Shannon, who lives in Walsall, said her father's death has left a huge void.
"The sun that you see outside, that is what represents my dad," she said.
"He was so full of life. He was energetic. He would never hold a grudge.
"So many people across the world have reached out to me with such nice words.
"It really breaks my heart. I'm only 24 and I never once thought about my dad dying.
"I need answers as to how and why."
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A spokesperson for Cambodia's national police told Sky News they did not have "anything to explain about Sonny's death" because officers had determined his death was from suicide.
"If they [the family] have suspicion [about the death], they can file a complaint," the spokesperson added.
"They can get a lawyer to file a complaint so [authorities] can investigate. The family of the deceased can file a complaint to get further investigation."
The Foreign Office says it is supporting the family and is in contact with Cambodian authorities.

The bones were discovered with the belongings of at least six women, police said, and Amairany Roblero's relatives have been told that evidence was found relating to her 2012 disappearance.
Ms Roblero was 18 when she vanished and, as is often the case in Mexico, her family was left to investigate her disappearance with little help from prosecutors.
Family friend Alejandra Jimenez said: "The prosecutors had the case file but they didn't ever give any results to her parents."
Instead, her parents printed flyers and gave them out near her school - the last place she was seen - but they had "nothing, nowhere to start, nor any directions to the end", Ms Jimenez added.
A suspect, identified only by his first name, Miguel, was detained by neighbours and police last week after he is alleged to have killed a seventh young woman.
He is accused of waiting for a woman to leave her apartment and then rushing inside to sexually abuse and strangle her 17-year-old daughter.
The woman returned to the apartment to see the suspect leaving and she was slashed across her neck before he ran off.
She survived but her daughter died.
Investigators searched a room rented by the suspect and found bones, mobile phones and ID cards belonging to several women in the same block, thought to be mementos.
Miguel is awaiting trial on charges of murder and attempted murder relating to the most recent victims.
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City prosecutor Ulises Lara insisted the suspect was difficult to catch because "he showed no signs of violent or aggressive behaviour in his daily life".
Ms Roblero's family and friends were not accepting this, however.
"They (authorities) have all the means to look for missing people," Ms Jimenez said. "Instead of focusing on their political campaigns, they should help all the women who are looking for their children."
Juan Carlos Gutierrez, a lawyer representing the family of another victim, was also frustrated, asking why no investigation had never been launched in that case, despite missing person reports being filed in 2015.
Ms Jimenez said Ms Roblero's family had not been told which of the items or remains in the apartment had been linked to her, adding: "This is wearing her parents down physically, mentally."
Some 2,580 women were murdered in Mexico in 2023, according to the country's National Public Security System but poorly funded and badly trained prosecutors have failed to stop serial killers over the years.
In 2021 a serial killer in Mexico City killed 19 people but their bodies were only found, buried at his house, after the wife of a police commander became one of the victims.
In 2018 another serial killer in Mexico City murdered at least 10 women and was only stopped after he was seen pushing a dismembered body down the street in a pram.

The incident has prompted the government of southeastern Caribbean nation to shut seven beaches and a marine park.
The attack occurred at Turtle Beach along Great Courland Bay on Tobago with the closure including beaches along the northwestern coast of the island.
The shark appeared to be a bull shark, according to the Tobago House of Assembly, and was 8-10ft long and 2ft wide.
Chief Secretary Farley Augustine said the 64-year-old man was in a "stable" condition but had suffered severe injuries to his arm, thigh and stomach.
A watersports manager at a beach hotel who saw the incident said the man was about waist deep in the water when the shark attacked.
He told local media their backs were turned, and they did not see the shark approaching.
"The other people in the water were physically trying to fight the shark off while it attacked," he added.
In a statement, the government said shark sightings were reported in the Grafton area and the Buccoo Reef Marine Park.
Officials said the closures will allow the coastguard and Department of Fisheries to investigate the incident and "neutralise the shark threat, if possible".
A Foreign Office spokesperson said: "We are supporting the family of an injured British man in Tobago and are in contact with the local authorities."
Last year, there were 69 unprovoked attacks and 22 provoked bites worldwide, along with 14 fatalities, according to the Florida-based International Shark Attack File.