The 91-year-old had been ill for a long time after fighting for nearly seven decades to make first the Soviet Union and then Russia a better place.
A leading Russian rights activist and former Soviet dissident has died at the age of 91.
Lyudmila Alexeyeva passed away in a Moscow hospital after a long illness.
For nearly seven decades she defended the cause of human rights in first the Soviet Union and then Russia. She faced many death threats from her beginnings in the 1950s, relentlessly pressing the Soviet authorities to improve human rights, through times of crushing repression and those of relative tolerance, a job that required enormous patience.
In 1976 she was a co-founder of the Moscow Helsinki Group, Russia's oldest human rights organisation.
Its members were arrested, jailed or forced into exile. Alexeyeva went into American exile the following year.
She returned to Russia in 1993 and became a critic of Vladimir Putin, opposing the imprisonment of Mikhail Khodorkovsky, and demanding the truth in the Magnitsky affair.
Kremlin suspicion of non-governmental organisations increasingly impeded her activities.
More recently Alexeyeva condemned the annexation of Crimea, "a shame for our country", and what she called the "political murder" of Boris Nemtsov.
Described as gentle yet courageous, In 2009, she was awarded the prestigious Sakharov Prize by the European parliament.
In 2014, she announced that the Moscow Helsinki Group had laid off most of its staff and cut pay for the remainder. The move followed declining foreign donations in the wake of legislation requiring groups receiving such funding to register as "foreign agents."