The widow of right-to-die campaigner Tony Nicklinson is taking his fight to the European Court of Human Rights.
Jane Nicklinson, from Melksham, Wiltshire, has formally lodged an application in her own right and on behalf of her late husband.
She is arguing the UK violated their human rights because MPs have not debated assisted dying.
Judges previously said it was for parliament to consider legalising assisted dying or see courts step in.
The Supreme court concluded in June last year it had the power to declare the current law criminalising acts of actively helping someone to take their own life, "incompatible" with human rights.
Lord Neuberger, president of the Supreme Court, said that if MPs and peers did not give serious consideration to legalising assisted suicide, there was a "real prospect" a future legal challenge would succeed.
Mr Nicklinson, who suffered from locked-in syndrome, died in 2012 aged 58 - days after losing a High Court case to allow doctors to end his life.
The civil engineer was paralysed from the neck down following a stroke in 2005 and described his life as a "living nightmare".
But, because he would need a doctor to administer a lethal injection, Mr Nicklinson was unable to travel to Switzerland for assisted dying, instead mounting a long legal challenge to overturn centuries-old laws on murder and manslaughter.
Mrs Nicklinson's lawyer Saimo Chahal, who also represents paralysed former builder Paul Lamb, from Leeds, said the Supreme Court had breached Article 8 of the European Convention on Human Rights by refusing to decide on the compatibility of the existing law on assisted dying.
"Jane has had no option but to take her fight to the European Court because the majority of the Supreme Court decided to refer the matter to parliament rather than grappling with the issue themselves," Ms Chahal said.
"Notwithstanding that, it was complicated and contentious they should have grasped the nettle.
"It does not look as if parliament are likely any time soon to review the ban on assisted dying and so Jane has lodged her application in Strasbourg."
In October, the Director of Public Prosecutions said the law on assisted suicide in the UK did not offer "immunity against prosecution" and the likelihood of health care professionals being prosecuted depends on their "specific and professional duty of care to the person in question".
It is thought Lord Falconer's bill on assisted dying, which has been debated in the House of Lords, will run out of time to become law before the general election.