Home Secretary Theresa May, who was ranked second in last year's inaugural Woman's Hour Power List, said Baroness Lawrence was "an example to us all".
Her son, an 18-year-old student, was stabbed to death by a group of up to six white youths in an unprovoked racist attack as he waited with a friend at a bus stop in south-east London on April 22 1993. It took more than 18 years to bring two of his killers to justice.
Mrs May said: "Faced by a terrible tragedy, she picked herself up and carried on fighting to ensure that justice could be done.
"What is most striking about this woman is the great strength that she has shown over decades - strength to carry on, to keep on going, even in the most difficult times when all seemed impossible.
"Also striking is the persistence that she has shown, because she has never given up. And finally, what is most impressive about this game-changer is that throughout it all, over the years, despite blow after blow, she has dealt with everything with absolute dignity."
The list of 10 women was revealed in a special live programme and included individuals involved in issues such as child poverty and internet safety.