Mr Ross has been self-isolating since Wednesday after being informed by Scotland Office minister David Duguid that the MP had tested positive for the virus.
The two men had been on a visit to Peterhead together on Monday, speaking to fishermen about the impacts of the pandemic.
The Scotland Office confirmed on Wednesday that Mr Duguid had taken a test as a precaution, but is not experiencing any symptoms and is said to be well.
Mr Ross was told by text on that morning about the positive test, by which time he was already in the Scottish Parliament building and so returned to the Edinburgh hotel he has been staying at, after speaking to staff.
The Scottish Conservatives also announced five members of staff and four MSPs were told to get tested “as a precaution”, with the same advice given to two MSPs from another party.
On Friday morning, a party spokesman said: “Douglas Ross has tested negative for Covid, as have all Scottish Conservative MSPs and staff who took a test as a precaution.
“Douglas will continue to voluntarily self-isolate as a precaution until Thursday, June 10.”
A spokeswoman for the Scotland Office said: “Minister Duguid is self-isolating after testing positive for coronavirus.
“He took a test as a precaution at a local UK Government test centre. He has notified those he was in close contact with.”