The Italian side travelled north having held a perfect record in the Europa Conference League, but rested numerous players on the synthetic turf in Norway.
Erik Botheim opening the scoring inside the first 10 minutes for Bodo/Glimt before Patrick Berg doubled their advantage in the 20th minute at the Aspmyra Stadion.
Carles Perez pulled one back for Mourinho's men in the 28th minute, but Roma went into half-time 2-1 down in their third Europa Conference League match of the season.
However, things turned sour for Mourinho's side in the second half as Botheim added his second in the 52nd minute.
Ola Solbakken scored his side's fourth before Amahl Pellegrino added a fifth, with the rout complete in the 80th minute when Solbakken completed his brace in the 80th minute.
The Norwegian side are famous for bringing novelty sized toothbrushes to games, but they drilled through their Italian opposition with ease.
Tammy Abraham came off the bench for the visitors, as did Henrikh Mkhitaryan, with Rui Patricio the unlucky shot-stopper to complete a triumvirate of former Premier League players.
Empoli 
Udinese 
CSKA Moscow 
Rubin 
Slovan Bratislava 
AC Milan 
Sparta Praha 
Atletico Madrid 
Valencia 
Barcelona 
Stade Brestois 29 
Bayer Leverkusen 
Red Bull Salzburg 
Bayern Munich 
Paris Saint Germain 
Inter 
RB Leipzig 
Manchester City 
Feyenoord 
Sporting CP 
Arsenal 
FC Rostov 
Spartak Moscow 
Aston Villa 
Juventus 
Celtic 
Club Brugge 
Dinamo Zagreb 
Borussia Dortmund 
Liverpool 
Real Madrid 
Monaco 
Benfica 
PSV 
Shakhtar Donetsk 
Lokomotiv Moscow 
Dinamo Moscow 
Anderlecht 
FC Porto 
AZ Alkmaar 
Galatasaray 
Dynamo Kyiv 
Viktoria Plzen 
Lazio 
Ludogorets 
Qarabag 
Lyon 
FC Heidenheim 
Chelsea 
FC Midtjylland 
Eintracht Frankfurt 
Manchester Utd 
Bodo/Glimt 
Nice 
Rangers 
Real Sociedad 
Ajax 
Tottenham 
Roma