Humanists UK announced that the father-of-two from Leeds died in hospital on Tuesday.
Mr Lamb, who lived in Swinnow, took on several legal challenges aimed at changing the law on assisted dying, taking his case to the Supreme Court in 2014.
The former builder campaigned to change the law on assisted dying for those who are either incurably suffering or terminally ill, and wanted the right-to-die when his pain became too much to bear.
Mr Lamb’s carer Francesca Hepworth has said she is “shocked” by his death, but expressed relief that he is “finally at peace” after suffering from chronic pain as a result of the car crash in 1990.
Mr Lamb was left with no function from the neck down aside from limited movement in his right arm and required 24-hour care.
Ms Hepworth said: “Paul’s death has been a shock to us all, but I’m glad he is finally at peace.
“For years, Paul grappled with his condition and faced increasing pain, discomfort, and distress.
“But throughout it all, what scared him the most was his utter lack of control, and the prospect of his pain becoming too much to handle.
“I know Paul was resolute in his belief that nobody should be forced to suffer, and determined to keep fighting to change the law on assisted dying.
“I only regret that he now won’t be able to see such a choice realised, if the law were to change.
“I’m proud to have known him, and been able to call such a brave and courageous man my friend. I am going to miss him.”
Speaking in November 2020, Mr Lamb, said: "I cannot understand, in a civilised society like ours, why I should be forced to suffer when millions of people around the world already have the choice I asked for.
"I have never wanted anyone to pity me. All I have ever wanted is for my choice to be respected and given equal validity under the law, like everyone else’s".
Humanists UK chief executive Andrew Copson said he would leave a “fierce legacy of campaigning”.
He added: “Paul Lamb was a tireless advocate for the right to die who dedicated his life to championing choice for those with terminal or incurable illnesses.
“He endured near constant pain and suffering. But despite this, Paul never accepted the injustice of our country’s ban on assisted dying for the incurably suffering, nor wavered in his determination to change the law.
“He leaves behind a fierce legacy of campaigning, which we are determined to continue in his honour. His death is a loss to us all, and our thoughts and wishes are with his friends and family.”