Source: Sharecast
She will be replaced by the biopharma’s chief commercial officer, Luke Miels, who has been with GSK since 2017.
Walmsley, who took over from fellow long-serving chief executive Andrew Witty in 2017, has led GSK through a period of significant change.
In particular, in 2022 she oversaw the spinning off its consumer health arm as Haleon, leaving GSK as a pure play drugs and vaccines specialist.
In a statement, Walmsley, 56, said: "2026 is a pivotal year for GSK to define its path for the decade ahead, and I believe the right moment for a new leadership.
"I look forward to supporting this transition and to cheering GSK’s future success as I begin my own new adventures."
Walmsley will step down from the board on 31 December, with Miels replacing her from 1 January 2026.
However, she will remain with the business - which is targeting sales of more than £40bn by 2031 - until the end of September 2026, to support the handover.
Jonathan Symonds, chair, said: "[Miels] has outstanding global biopharma development and commercial experience, together with a deep understanding of the company, its prospects and its people. He is extremely well placed to lead, deliver and surpass the ambitions we have set for GSK."
GSK added that Miels, who has world-wide responsibility for medicines and vaccines, had been "instrumental" in building the firm's speciality medicines portfolio, particularly in oncology and respiratory.
His base salary as chief executive will be £1,375,000, with an on-target annual bonus of 150%, rising to a maximum of 300%.
Walmsley took home a total of £10.6m in 2024, including bonuses and other benefits. That was, however, less than Pascal Soriot, her counterpart at fellow blue chip drugs firm AstraZeneca, who was paid £14.7m.
Walmsley’s base salary was £1,430,792 last year.
As at 1230 BST, shares in GSK had put on more than 2% at 1,522.5p.
Russ Mould, investment director at AJ Bell, said: “It can never be great for a CEO’s ego when a share price goes up on news of their departure.
“Emma Walmsley has been patiently leading a turnaround of the pharmaceutical giant almost ever since she took over, and she can point to real evidence of progress including the spin-off of Haleon.
“However, litigation issues over Zantac and setbacks for its vaccine business have held the business back.
“While it may not be reflected in the share price, Miels could be grateful in the longer term for the progress Walmsley has made in the background.”
Derren Nathan, head of equity research at Hargreaves Lansdown, said: “One of Walmsley’s key achievements was the demerger of Haleon. That not just strengthened GSK’s balance sheet but also sharpened the group’s focus on speciality medicines and vaccines.
“Her reign also saw a line drawn in the sand in the Zantac litigation, removing a key financial uncertainty.
“Despite the progress, the share price performance has been lacklustre, and the stock trades at a significant discount to the peer group.”
