One of the most important facts to know about investing is that dividend-paying stocks far outperform their non-dividend-paying counterparts over the long term. This means that every long-term investor should own at least one dividend-paying stock, and depending on your age, investment goals, and risk tolerance, maybe even a diversified portfolio full of them.

With this in mind, let’s take a look at three high-yielding stocks that you could add to your portfolio today.

1. Crombie Real Estate Investment Trust: 6.7% yield

Crombie Real Estate Investment Trust (TSX:CRR.UN) is one of Canada’s largest owners and operators of commercial real estate. It pays a monthly distribution of $0.07417 per share, or $0.89 per share annually, giving its stock a 6.7% yield at today’s levels.

Investors should also note that Crombie has maintained this monthly rate since May 2008, but its increased amount of funds from operations, including 10.1% year-over-year growth to $33.7 million in the second quarter and 7.7% year-over-year growth to $64.9 million in the first half of fiscal 2015, could allow for a slight bump within the next few months.

2. Great-West Lifeco Inc.: 3.9% yield

Great-West Lifeco Inc. (TSX:GWO) is one of the world’s leading providers of financial products and services, including life insurance, health insurance, and asset management. It pays a quarterly dividend of $0.326 per share, or $1.304 per share annually, which gives its stock a 3.9% yield at current levels.

It is also worth noting that Great-West Lifeco raised its dividend by 6% in February, its first increase since 2008, and its consistent cash flows from operating activities, including $5.44 billion in fiscal 2014 and $2.5 billion in the first half of fiscal 2015, could allow it to maintain its new rate for the next several years.

3. WSP Global Inc.: 3.2% yield

WSP Global Inc. (TSX:WSP) is one of the world’s leading providers of engineering and design services to numerous industries. It pays a quarterly dividend of $0.375 per share, or $1.50 per share annually, giving its stock a 3.2% yield.

Investors should also note that WSP Global has maintained this quarterly rate for the last several years, but its increased amount of funds from operations, including 108.7% year-over-year growth to $79.1 million in the second quarter and 117.7% year-over-year growth to $140.2 million in the first half of fiscal 2015, could allow for a significant increase in its third- or fourth-quarter earnings release.

Which of these dividend stocks belongs in your portfolio?

Crombie REIT, Great-West Lifeco, and WSP Global are three of the most attractive dividend-paying investment opportunities in their respective industries. Foolish investors should take a closer look and consider initiating positions in one of them today.

Want three more of our TOP dividend stock picks?

These three top stocks have delivered dividends for shareholders for decades (and even centuries!). Check out our special FREE report: "3 Dividend Stocks to Buy and Hold Forever". Click here now to get the full story!

NEW! This Stock Could Be Like Buying Amazon In 1997

For only the 5th time in over 14 years, Motley Fool co-founder David Gardner just issued a Buy Recommendation on this recent Canadian IPO.

Stock Advisor Canada’s Chief Investment Adviser, Iain Butler, also recommended this company back in March – and it’s already up a whopping 57%!

Enter your email address below to claim your copy of this brand new report, “Breakthrough IPO Receives Rare Endorsement.”

Fool contributor Joseph Solitro has no position in any stocks mentioned.