Sir Keir Starmer said he wants a future "defined by hope", not prejudice in a touching message to his daughter on International Womens Day.
"To my daughter, you are my pride and joy", the prime minister wrote in an Instagram post, adding that he does his job for her generation.
Other ministers have marked the day with pledges to tackle the gender pay gap and give women a better start in life, as Labour peer Baroness Harriet Harman starts her new role as the UKs special envoy for women and girls.
The government said it is "accelerating action to change womens lives" on this day as part of its Plan for Change.
Sir Keirs message to his daughter, said: "Its for you, and your generation, that I do this job.
"To make sure your skills and talents determine how far you go, not your gender.
"To make your future is defined by hope, security and opportunities, not prejudice and limits.
"On International Womens Day, we celebrate the achievements of women before you, and look forward to the achievements possible in an equal world."
Meanwhile, Baroness Harman - who has advocated for women and girls throughout her career - called her appointment as the UKs special envoy for women and girls, a "great honour".
She served as Peckhams MP for more than 40 years, and held a number of ministerial roles including the women and equalities brief in the New Labour governments of Sir Tony Blair and Gordon Brown.
"Over the last decades we have made tremendous strides towards ending womens inequality," Baroness Harman said, adding that the job is "far from done".
"The UK will, in coalition with women around the world, play a key role in standing up for the rights of all women and girls at a critical time."
Foreign Secretary David Lammy said he was "delighted" to appoint her, adding that "action on equality for women and girls is vital to delivering the global economic growth we need and, a safer, more secure world."
But her appointment has also drawn criticism. ActionAid UKs co-chief Hannah Bond, said that without new funding, her appointment was "papering over the cracks" of a struggling aid sector.
Ms Bond said that while the appointment is a "welcome step", especially with Baroness Harmans "strong track record... without funding to back it up, it risks being more symbol than substance."
The response comes after Sir Keir cut foreign aid spending to fund defence commitments he said were necessary to protect the UK amid uncertainty over the future of the Ukraine war and its implications for European security.