The episode was seen by an estimated 2.18 million household viewers and gained a 1/3 ratings share among adults aged 18–49, according to Nielsen Media Research.
While Amy (Melissa Fumero) stays to work on the wedding, Jake and Gina (Chelsea Peretti) accompany Adrian to retrieve his grandmother's earrings from a pawn shop.
In its original American broadcast, "Monster in the Closet" was seen by an estimated 2.18 million household viewers and gained a 0.9/3 ratings share among adults aged 18–49, according to Nielsen Media Research.
With these ratings, Brooklyn Nine-Nine was the second highest rated show on FOX for the night, beating Scream Queens but behind New Girl, seventh on its timeslot and fourteenth for the night, behind New Girl, The Real O'Neals, The Flash, NCIS: New Orleans, Fresh Off the Boat, Chicago Fire, Bull, David Blaine: Beyond Magic, American Housewife, The Middle, NCIS, The Voice, and This Is Us.
"[3] Allie Pape from Vulture gave the show a perfect 5 star rating out of 5 and wrote, "'Monster in the Closet' is one of the funniest Brooklyn Nine-Nine episodes has ever done.
Amy's dream of getting to organize a wedding in less than 24 hours, and the way it turned into a nightmare as everyone but Scully and Hitchcock proved to be incompetent and/or drunk, provided good material for Melissa Fumero and a lot of the cast.
"[5] Andy Crump of Paste gave the episode a 9.2 and wrote, "It's like looking at the Bizarro World version of the 9-9: Amy is a savage, Scully and Hitchcock are useful, Rosa is coming undone at the seams, Holt is petty, and Jake is an unwitting vessel for the universe.
'Monster in the Closet' winds up the threads of the Figgis story arc and reunites Rosa and Adrian, but more than that it lobs nothing but beautiful, joking perfection at us from start to finish.