The 83-year-old, appearing at his former grade school in Omaha, Neb., in honor of American Education Week, said on "CBS This Morning," "I don't know what stocks will do next week or next month or next year. Or five or ten years from now, I would say that they're very likely to be higher."
The Dow hit 16,000 for the first time on Monday, and the index has gained more than 3,000 points this year alone. Some analysts believe investors could be riding the bull market into a bubble.
Asked if he thinks stocks are overpriced (investor Carl Icahn has called them a "mirage"), Buffett said, "I would say that they're in a zone of reasonableness. Five years ago, I wrote an article for The New York Times that said they were very cheap. And every now and then, you can see that that they're very overpriced or very underpriced. Most of the time, they're in an area where maybe they're a little high, a little low, and nobody really knows exactly. They're definitely not way overpriced. They're definitely not underpriced."
Buffett said he doesn't have concerns about the market, taking the long view.
"We look at owning stocks as owning parts of business, just like owning a farm or an apartment house," he said. "And if you buy the right farm or apartment house or the right business through a stock, and you don't try and guess whether it's going to go up next week or next month, but you hold it for five or 10 or 20 years, you're going to do very well."
Turning to Buffett's recent investment in Exxon and news that the U.S. is becoming a world leader in oil production, Buffett said it's very important for America "because we've had a huge deficit in our balance of payments."
He added, "A good bit of that is because of oil and now, we're reducing our dependence dramatically on foreign oil. And that means we've reduced the number of dollars that flow out of this country to buy oil from the rest of the world. So it's a very important event."
In addition to being a businessman, Buffett is also a proponent of financial education. He's at the helm of the initiative, Grow Your Own Business Challenge, for kids ages 7 to 14, who get a chance to meet Buffett and pitch him ideas and win a monetary prize.
He said children need to learn about money and work habits and saving "very, very early on."
"It is the habits that you develop when you're young, you live with when you're older," he said. "Someone once said the chains of habits are too light to be felt until they're too heavy to be broken. And you want to have the right habits. And the time to get them is very young."
For more on Buffett's initiative for kids and to watch his full interview, check out the video above.