Hold on, skip merging

For this approach, you do not want to merge your feature_a into feature_b repeatedly.

Rebasing has been mentioned in other answers, but only for rebasing things onto master. What you want to do in your case is:

• Start your feature_b from feature_a, i.e.:

   git checkout feature_a git checkout -b feature_b 

• Whenever feature_a changes while it is waiting to get merged into master, you rebase feature_b on it:

   ... commit something onto feature_a ... git checkout feature_b git rebase feature_a 

• Finally, as soon as feature_a has been merged into master, you simply get the new master and rebase feature_aonto it a last time:

   git checkout master git pull origin master git checkout feature_b git rebase --onto master feature_a feature_b 

This final rebase will graft all commits that are dangling from the feature_acommit (which is now irrelevant as it has been merged into master) right onto master. Your feature_b is now a simple, standard branch going right from master.

Hold on, skip merging

For this approach, you do not want to merge your feature_a into feature_b repeatedly.

Rebasing has been mentioned in other answers, but only for rebasing things onto master. What you want to do in your case is:

• Start your feature_b from feature_a, i.e.:

   git checkout feature_a git checkout -b feature_b 

• Whenever feature_a changes while it is waiting to get merged into master, you rebase feature_b on it:

   ... commit something onto feature_a ... git checkout feature_b git rebase feature_a 

• Finally, as soon as feature_a has been merged into master, you simply get the new master and rebase feature_aonto it a last time:

   git checkout master git pull origin master git checkout feature_b git rebase --onto master feature_a feature_b 

This final rebase will graft all commits that are dangling from the feature_acommit (which is now irrelevant as it has been merged into master) right onto master. Your feature_b is now a simple, standard branch going right from master.

EDIT: inspired from the comments, a little heads up: if you need to make some change which affects both features, then be sure to make it in feature_a (and then rebase as shown). Do not make it in two different commits in both branches, even if may be tempting; as feature_a is part of the history of feature_b, having the single change in two different commits will be semantically wrong and possibly lead to conflicts or "resurrections" of unwanted code, later.