Big Tree with branches neighbours yard

Neighbour A has a couple big trees at the edge of the fence and now the branches have grown over the fence and are overhanging into Neighbour B's backyard. Does neighbour B have the option of cutting the branches of Neighbour A's tree?

I would cut them.

Where do you live ? You may want to check the by-laws first.

For example, from my understanding of the Toronto by-law, you need your neighbour's permission. Also, if the tree is a "big" tree, you will need to hire a qualified tree expert

http://www.toronto.ca/faq/trees.htm#q2

it says

Three main points to remember when dealing with trees on adjacent private property are that:

You cannot trespass onto your neighbour's property;
You cannot damage your neighbour's property (in this case a tree); and
You have the right to maintain your property in a safe condition

It is therefore best for property owners to come to an agreement between themselves with respect to trees overhanging property lines.

If you are unable to reach an agreement with your neighbour and want to determine your legal rights, you should contact a lawyer.

The act of pruning trees on neighbouring private property affects private property rights and is a civil issue between private property owners.

The City has no jurisdiction with respect to such issues.

Where a tree on private property is protected under the provisions of the Private Tree Bylaw, pruning of the tree is permitted provided the pruning is in accordance with good arboricultural standards. Otherwise, a permit would be required to injure or destroy the tree.

A qualified tree expert should always be retained to carry out tree pruning.

1) go talk to them. Much easier to simply come to an agreement.

2) In most cities, you can trim the branches on your side, however you cannot trim it so much that it kills the tree. If you do, the neighbour can likely sue you for the replacement of the tree.

Seriously, #1 is so much easier.