The firm secured the accolade for Project Sky, an initiative designed to remove obstacles to female career progression, improve the number of women at senior levels and to create a better workplace for all.
The work of the firm’s Family Support Network and the role the initiative plays in supporting working parents, carers, and modern families was also recognised by the judges.
Head of Responsible Business at Pinsent Masons, Kate Fergusson, said: "We are delighted to have won this award in recognition of the transformational change we have implemented across the firm. Under the leadership of Head of Employment, Linda Jones, Project Sky has gone from strength to strength helping the firm to increase the number of female partners to 23% this year, compared to 19% in 2013.
"Ensuring career progression and opportunity is available to all is crucial to the success of our business. The impact of becoming a parent or carer or being out of the business for any length of time on family leave isn't exclusively a female concern. We recognised that more needed to be done to support all of our working families.
"We have acted on this and have a suite of webinars, events and support sessions which have helped implement genuine cultural change and support employees across the firm."