Crowds in York, Hull and Leeds chanted, waved banners and decorated themselves in the Ukrainian colours of blue and yellow at the events, many of which were co-organised by pressure groups against war.
Many parents brought their children to the rallies.
In Leeds, 500 people marched from Briggate to the city’s Town Hall, with some members weeping as they heard speeches declaring “refugees are welcome here.”
Polina Merkulova, of Feminist Anti-War Resistance said: “The support in Leeds has been amazing as can be seen from the turnout today.”
And Richard Wilson, of Leeds for Europe told crowds: “We need to be going harder with the sanctions to end this peacefully. Our government needs to do more.
“We all need to be united to defeat this evil.”
Labour’s Rachael Maskell and Conservative Julian Sturdy both spoke at the event, and Stephen Cottrell, the Archbishop of York, led the crowd in prayer.
Ms Maskell said: “It is so important that we come together now as a City. In watching the atrocities unfold, we can feel so helpless, but when we come together, stand together and send our solidarity to the people of Ukraine together, we too play our part in calling for this war to end and justice for the Ukrainian people.”
Mr Sturdy said: “The world has been united in condemnation at Russia’s unprovoked aggression, in awe at the incredible acts of bravery by Ukrainian’s defending their homeland, and in sympathy with those fleeing their homes.
“My inbox has been filled with heartfelt messages from residents who want to do more to show solidarity and help our Ukrainian neighbours.”
In Hull, crowds rallied on Saturday in the city’s King Edward’ Square.
And Demonstrators in Londondenounced Russian President Vladimir Putin as a “delusional lunatic” and a “bully” as hundreds gathered in the capital to protest his invasion of Ukraine.
Campaigners gathered outside the BBC’s Broadcasting House to wave signs saying “Russian troops out” and “No Nato Expansion”.
The march was held by the Stop the War Coalition, as well as the Campaign for Nuclear Disarmament , the No to Nato network, and CODEPINK.
Stop the War has caused controversy in recent months for its Nato-critical stance.
It has described itself as opposed to the British Government’s “aggressive posturing” and Nato’s “eastward expansion”.
But it has repeatedly been accused of harbouring anti-Western sentiments.
One male protester, who did not give his name, said Nato countries were “provok[ing] Putin”.
However, some marchers voiced differing opinions on the bloc.
Monika Lichomska, a Polish warehouse worker, said she was there to show her support for Ukrainians and believes Nato support can offer security.
“In Poland, we are secure because of Nato. But if we’re not stopping (Russia) now they will come after our country,” the 37-year-old, who described Mr Putin as a “delusional lunatic”, said.
Protesters chanted “Stop the war” and “Russian troops out now” as they began their march, with speeches heard at Trafalgar Square.