I disagree with the woman who suggested ignoring bad behavior. Your son is testing the limits. In a way, he's trying his wings and wondering how far he will be allowed to go. I have four children (15, 8, 5, and 3) My five-year-old is starting this behavior, but it is normal. But it is your responsiblity as the parent to show him where the boundaries are. I'm not talking about being mean, but being firm and consistent. I tell my son, "You are not allowed to talk naughty to Mommy. Please do as you are told or you'll have to spend time in time out." Then DO IT. Don't threaten punishment, then back down. And don't start the timeout clock/timer whatever until he's compliant. If he's still talking back, say "I'm not going to argue with you. I'm in charge, and you are in time out for talking back. It's time to be quiet now until time out is done." If he still keeps it up, you have to send him to bed, or he loses the chance to do something he was looking forward to, or some other privilege. The first time will be the hardest because he will still be trying to push that boundary. But you and your husband need to discuss your strategy in advance of the next episode and present a unified front. If your son sees you are on the same page and you aren't backing down, he'll change his behavior. You don't have to be angry...just let him know you love him, but you are willing to do whatever it takes to change the behavior. For example, we recently started to teach our three-year-old son that he needed to use "please" and "thank-you". He started using thank you, but absolutely refused to say please. He would turn his nose up and dig his heels in and demand what he wanted. This usually revolved around a drink or a snack. After getting frustrated and feeling at our wits ends, we decided to try making a game of it. Next time my husband was rough-housing with him, he was gently tickling him and when he wanted him to stop, he said, "Say the magic words! Say please stop!" My son did and my husband immediately stopped. He loved that game, and he learned that if he said please, he got what he wanted. He still refused to say please for food, so we decided to turn the tables on him. Whenever he demanded a glass of juice, we simply gave him a glass of water. When we gave it to him, he got angry, of course, and demanded his juice. We just said, "I'm sorry, but I can't give you juice until you say please. Say 'juice, please'" He refused for a week until he finally gave in and asked for juice and said please. We nearly fainted, and thank goodness we weren't out of juice that day!