Ban is closely following events in Brazil and "trusts that the country's authorities will honor Brazil's democratic processes, adhering to the rule of law and the constitution," his spokesman said in a statement.
He "calls for calm and dialogue among all sectors of society," the statement added.
Rousseff was suspended to face impeachment trial, ceding power to her vice president Michel Temer.
Brazil's first female president denounced the Senate vote to impeach her as a "coup" and urged her supporters to mobilize to defend her.