The Court of Arbitration for Sport cut nine months off the suspension imposed on Sharapova, who tested positive for meldonium at the Australian Open in January.
Sharapova, a five-time Grand Slam champion and former No. 1-ranked player, appealed to CAS in June seeking to overturn or reduce the two-year suspension imposed by the International Tennis Federation.
The CAS panel found that Sharapova "bore some degree of fault" for the positive test, saying a 15-month sanction was "appropriate."
The ban took effect on Jan. 26 and was originally due to run until Jan. 25, 2018. Now she will be eligible to return nearly a year earlier.
"I've gone from one of the toughest days of my career last March when I learned about my suspension to now, one of my happiest days, as I found out I can return to tennis in April," Sharapova said in a statement.
"In so many ways, I feel like something I love was taken away from me and it will feel really good to have it back," she added. "Tennis is my passion and I have missed it. I am counting the days until I can return to the court."
Steve Simon, CEO of the WTA tour, welcomed the ruling.
"We are pleased that the process is now at completion and can look forward to seeing Maria back on court in 2017," he said.
An independent ITF panel had found that Sharapova did not intend to cheat but that she bore "sole responsibility" and "very significant fault" for the positive test.
The panel also said the case "inevitably led to the conclusion" that she took the substance "for the purpose of enhancing her performance."
Sharapova acknowledged taking meldonium before each match at the Australian Open, where she lost in the quarterfinals to Serena Williams.
Sharapova said she was not aware that meldonium, also known as mildronate, had been included on the World Anti-Doping Agency's list of banned substances from Jan. 1, 2016.
The ITF said she also tested positive for meldonium in an out-of-competition control in Moscow on Feb. 2.
The 29-year-old Sharapova missed this year's French Open, Wimbledon and U.S. Open, as well as the Olympics in Rio de Janeiro.
Sharapova said she was first prescribed the Latvian-made drug, typically used for heart conditions, by her family doctor for various medical issues in 2006. She cited a bout of the flu, possible onset of diabetes and a magnesium deficiency.
Meldonium increases blood flow, which improves exercise capacity by carrying more oxygen to the muscles.
More than 100 athletes, including many Russians and other eastern Europeans, tested positive for meldonium early in the year. Some escaped with no sanctions because they argued successfully that they stopped taking the drug before Jan. 1 and that traces had lingered in their system. Sharapova, however, acknowledged that she used meldonium after Jan. 1.