In a joint statement released after a virtual summit on Friday, G7 leaders raised their overall commitment to $7.5bn (£5.3bn).
Wealthy countries are facing growing pressure to make sure lower-income nations get fair access to vaccines.
President Joe Biden has pledged $4bn in US aid to the fund.
An initial $2bn will be donated in 2021, with an additional $2bn coming over the next two years.
Germany pledged an additional $1.2bn with Chancellor Angela Merkel telling journalists: "I stressed in my intervention that the pandemic is not over until all people in the world have been vaccinated."