Aysha Frade, 43, was crossing Westminster Bridge on her way to pick up her daughters, aged eight and 11, from school when terrorist Khalid Masood struck.
The teacher, who grew up in Notting Hill, worked at nearby DLD London College.
A week after the horrific attack her family praised “amazing and irreplaceable” Mrs Frade in an emotional statement.
It read: “Our beloved Aysha; caring daughter, loving sister, amazing wife, irreplaceable aunt, thoughtful, supportive friend and the best and coolest of mummies.
"You were ripped away from our lives in the cruellest and most cowardly of ways. We now pray that you guide and protect not only us, but all of London, from further evil.
"You will always be remembered as our guardian angel who never shied away from facing up to bullies.
"There are no words to even begin to describe the crushing pain and eternal void left in our hearts."
Mrs Frade was one of four victims of the attack which injured more than 35 people.
American national Kurt Cochran and south London window cleaner Leslie Rhodes were also killed on the bridge.
Met Police officer Pc Keith Palmer was fatally stabbed by Masood as he tried to stop him entering the Palace of Westminster.
The attacker was shot dead by police.