The case against 52-year-old Gregory Elliot is based on a complaint from self-described political feminist Stephanie Guthrie, the Toronto Star reported.
She told police she first had online exchanges with Elliot in April when she was looking for a graphic designer and his work in the field came to her attention.
In August, Guthrie said she became concerned with Elliot's messages and asked him to "halt all communication," 680 News reported.
However, the undisclosed messages allegedly continued, and she called police to complain.
"Blocking [a Twitter account] doesn't stop a person from tagging you in their tweets," she told the Star.
Elliot is charged with criminal harassment, police said.