To dream that you are laughing, suggests that you need to lighten up and let go of your problems. Don't put so much pressure on yourself. Laughing is also a sign of joyous release and pleasure.
If you are being laughed at, then it indicates your insecurities and fears of not being accepted.
To hear the cheerful laughter of children, denotes splendid joy and vital health.
To dream that you or others are smiling, signifies that you are pleased with your achievements and approve of the decisions you have made. You will be rewarded for the good things you've done for others. Alternatively, you may be seeking for something or someone that will make you happy.
I have no clue how long I have laughed in my sleep because my sweet Thomas is the only one who ever said anything about it. Yet, I laugh heartily and sometimes it is an echo of my own father's laugh. No matter, it is just good we have a "DO DISTURB" policy.