Depending on your investing objectives, dividend growth investing can be a great investing strategy. When stocks are selected properly and your portfolio is diversified, your passive income can steadily grow over time.

The most proven dividend-paying companies have grown their payouts for at least 50 straight years, and are referred to as Dividend Kings. Here are two dividend growers that are so dependable you should be able to count on them to provide you with ever higher dividend income for the next few decades.

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1. PepsiCo: A titan of the global snacks and beverages industry

Everybody around the world knows PepsiCo (PEP 0.12%) for the countless billion-dollar snack foods and beverage brands within its portfolio. These include Lay's potato chips, the eponymous Pepsi-Cola, Doritos chips, and the Gatorade sports drink. This stacked product lineup has paid dividends for shareholders over the years.

Most recently, the company just announced its 51st consecutive year of dividend growth with a 10% hike in the quarterly dividend, which will be paid in June of this year.

Considering that PepsiCo's 2.7% dividend yield is well above the S&P 500 index's 1.7% yield, that's an especially generous dividend raise. And this double-digit increase means that if anything, dividend growth is speeding up from its nearly 8% annual rate over the last 10 years.

With its tremendous portfolio of brands and bolt-on acquisitions to bolster its growth prospects, it's not hard to see why management was confident enough to hand out such a big pay boost to shareholders. Analysts believe that PepsiCo's non-GAAP (adjusted) diluted earnings per share (EPS) will grow by 7.6% each year over the next five years. This should allow for many more years of strong dividend growth since the company's dividend payout ratio will be around 67% in 2023.

Best of all, dividend growth investors can scoop up shares of this consumer staple at a forward price-to-earnings (P/E) ratio of 22.1. For context, that's close to the non-alcoholic beverages industry average forward P/E ratio of 21.3. That's a more than reasonable premium valuation for a proven Dividend King such as PepsiCo in my opinion.

2. Abbott Laboratories: A quality healthcare company

Most people will probably recognize Abbott Laboratories (ABT 2.48%) for its BinaxNOW COVID-19 rapid tests and its consumer-facing brands like Similac infant formula. But the medical devices business headed up by the continuous glucose monitoring (CGM) brand named FreeStyle Libre plays just as much of a role in generating revenue for Abbott.

Overall, the company enjoys market-leading positions in multiple categories within the medical devices industry (e.g., CGMs, heart pumps, and stents), nutrition, and diagnostics.

Abbott's impressive product portfolio enabled it to be kind to its shareholders over the decades: The company's most recent 8.5% dividend increase declared last December was the 51st year in a row. When its dividend growth is paired with its market-topping 2% dividend yield, Abbott becomes a compelling dividend growth stock. This is especially the case considering that the company's payout ratio will come in at approximately 46% in 2023.

Along with the 8.3% annual adjusted diluted EPS growth that analysts expect from Abbott over the next five years, this sets it up for more solid dividend growth in the future. Topping it all off, shares of the stock can be picked up at a forward P/E ratio of 21.2. This is meaningfully below the medical devices industry average forward P/E ratio of 24.8, which makes Abbott a smart buy for dividend growth investors.