The gas, power and utility company said it will increase its monthly payment to shareholders by half a cent to 12.5 cents per common share with the next payout in May.
At the current share price, AltaGas stock will yield about four per cent annually.
The dividend increase came as the company reported a profit of $49 million or 45 cents per diluted share compared with a profit of $41.3 million or 45 cents per diluted share a year ago, when it had fewer shares outstanding.
The company said "normalized" net income was $55.5 million, up from $40.1 million a year ago.
Revenue for the three months ended March 31 was $613.5 million, up from $361.7 million a year earlier, boosted by the acquisition last year of Semco Holding Corp., which operates natural gas utilities in Alaska and Michigan.
"We are pleased to report strong first quarter earnings driven by our diversified portfolio of energy infrastructure assets including our new utilities in the United States," AltaGas chairman and chief executive David Cornhill said.
"The increase in our dividend is a reflection of the stable and predictable cash flow growth we are starting to realize from our recent growth and it is a key part of the overall value proposition that we offer our shareholders."
Last month, AltaGas agreed to pay US$515 million to buy Blythe Energy LLC, which owns a 507-megawatt power plant in Southern California.
In addition to the natural gas-fired generator, the purchase from affiliates of LS Power Equity Advisory LLC includes major spare parts and a 108-kilometre transmission line in the state.