Yes, but washing instructions vary from model to model. Always check the tags. It’s usually best to avoid driers; however, sometimes a light tumble dry can be a good way to restore loft.
Be extra careful when it comes to down sleeping bags. Use a gentle wash cycle and cold water. Front-loaders are best since the agitator of a top-loader can damage your bag. Throw in a few tennis balls to keep the insulation from migrating and clumping. Be sure it’s completely dry before storing.