The group of six, who work at both Brasserie Blanc and The White Brasserie Company, will tackle the 4,808m peak on the French-Italian border from 10-14 September.
The climb is to commemorate the lives of their former colleague Rob White and Tim Bacon, the restaurateur behind brands including Gusto and The Alchemist, who passed away last year.
The team are aiming to raise £12,000 for the Tim Bacon Foundation and The Christie Hospital, where both Bacon and White were treated while suffering from cancer.
Their efforts will support an overall £25,000 target set by the restaurant group, which is donating £1 from the sale of every Mont Blanc dessert ordered at Brasserie Blanc to the cause.
A series of charity jazz dinners are also being held at Brasserie Blanc St Albans (12 September), Oxford (13 September) and Knutsford (19 September), where diners can enjoy a three-course meal and glass of wine accompanied by music from the Pocket Orchestra for £30.
Donations for the Mont Blanc Challenge can also be made online at https://www.justgiving.com/companyteams/MontBlancChallenge
The team will be updating their progress on social media using #BlancClimbsBlanc.