|"Are you a wizard or not?"
Second Wizarding War
- "So, we've given a dozen different houses every protection we can throw at them. They all look like they could be the place we're going to hide you, they've all got some connection with the Order: my house, Kingsley's place, Molly's Auntie Muriel's – you get the idea."
- —Alastor Moody instructs Harry Potter on how he will be moved from Privet Drive, in 1997.[src]
Although Muriel was not a member of the Order of the Phoenix, her niece's family was, and she allowed their home to be used as one of the Order's safehouses. In late July of 1997, it was one of the locations Order members retreated to after the Battle of the Seven Potters. Ronald Weasley and Nymphadora Tonks fled there after evading Bellatrix Lestrange's attacks, but managing to injure Rodolphus Lestrange. They ended up missing their Portkey to The Burrow, and Muriel "fussed" over them.
In early 1998, when the Death Eater regime found out Ronald Weasley was hunting down Voldemort's Horcruxes with Harry Potter and Hermione Granger, the Weasley family moved to Muriel's and placed a Fidelius Charm around the house. Unable to run their shop Weasleys' Wizard Wheezes in Diagon Alley, Fred and George Weasley started operating an Owl-Order business out of Muriel's back room, much to her chagrin. Mr. Ollivander later moved to Muriel's too. 
- Harry Potter and the Deathly Hallows (First mentioned)