Announcing the split on Friday, the Polish superstar said it was a mutual decision.
During the three years Swiatek worked with Wiktorowski, she won four of her five grand slam singles titles and rose to the top of the women's rankings.
"After 3 years of the greatest achievements in my career, together with my coach Tomasz Wiktorowski we decided to part way," Swiatek wrote in a post on Instagram.
"I want to start with a big thank you and appreciating our work together."
Swiatek appointed Wiktorowski as coach at the end of the 2021 season. He helped her capture 19 of her 22 career titles and an Olympic bronze medal in Paris in August.
"Coach Wiktorowski joined my team for three seasons, when I strongly needed changes and a fresh approach to my game," Swiatek said.
"His experience, analytical and strategic attitude and enormous knowledge about tennis helped us to achieve things I've never dreamed of only a few months after we started working together.
"Our main goal was to become No.1 player in the world and coach Wiktorowski was the one who said it first."
Swiatek hasn't competed since losing to Jessica Pegula in the quarter-finals of last month's US Open.
She withdrew from this week's China Open in Beijing - where she would have been defending champion - citing personal reasons.
The 23-year-old also pulled out of the recent Korea Open in Seoul, citing fatigue.
"Due to this important change on my team, I give myself a couple of weeks to start a co-operation with a new coach," Swiatek wrote.
"I'm in the middle of first talks with coaches from abroad (non-Polish) because I'm ready to take the next step of my career. I will let you know when I make a decision."
Wiktorowski was voted the WTA's Coach of the Year by his peers last year.
"Coach, THANK YOU, I wish you all the best," Swiatek wrote.
"I know that you would like to rest after these 3 years of hard work and traveling (sic) a lot and spending some well deserved time with your loved ones and I hope you'll get what you need."
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