It has been a part of the Promise for over a century, but from now on girls will no longer pledge their devotion to God when they join the Guides.
Girlguiding has announced it has dropped the phrase "to love my God" from its Promise after a consultation suggested that different words are needed to include non-religious youngsters and those of other faiths.
Instead, girls joining the organisation will now be asked to "be true to myself and develop my beliefs". A mention of vowing to love or serve God has been included in the Promise since the Guides began in 1910.
Originally, new members were asked to "do my duty to God", and this was changed to "love my God" in 1994.
The move has been welcomed by secular groups who said it was a "hugely positive" development.
The new Promise also asks guides "to serve the Queen and my community" instead of "the Queen and my country".
Around 44,000 people responded to the consultation on changing the wording of the oath, Girlguiding said.
Chief Guide Gill Slocombe said: "Girlguiding believes passionately that girls need a space to explore their values and build the confidence to be true to themselves. Guiding has always been somewhere that all girls can develop their beliefs and moral framework, both inside and outside the context of a formal religion.
"However, we knew that some people found our Promise confusing on this point and that it discouraged some girls and volunteers from joining us. We hope that the new wording will help us reach out to girls and women who might not have considered guiding before - so that even more girls can benefit from everything guiding can offer.
"Guiding believes in having one Promise that is a clear statement of our core values for all our members to commit to. We hope that our new Promise will allow all girls - of all faiths and none - to understand and feel proud of their commitment."