Hostels
Anker Hostel, Storgata (tram 11-12-13-17, bus 30-31 to Hausmanns gate), ? +47 22 99 72 00. 290 beds. Very centrally located, 5 minutes walk to the central station or Grünerløkka. Dorm bed: NOK 200-250.  edit
Haraldsheim Youth Hostel, Sinsenkrysset (tram 17 or bus 23-24-31-33, 4 km from downtown Oslo). The biggest HI hostel in Oslo. Not too far from the action (but it is hard to find), walking distance to the lively neighbourhoods of Torshov and Grünerløkka. Located in a very quiet area of Oslo, this is a place you'd go to sleep, not to party. The breakfast is outstanding for a hostel and is vegan-friendly, although with reduced choice. It is advisable to reconfirm your booking before you come and inform at what time you are going to arrive although the reception is open 24 hours. Double room: NOK 620; Dorm bed: NOK 240, breakfast included.  edit
Oslo Holtekilen Hostel, Stabekk/Kveldsroveien (train to Stabekk, or bus 151, 153, 161, 162, 252 or 261 to Kveldsroveien). HI hostel. Outside the city border, extra fee needed if you have Oslo Transport card. Open May-August. In a picturesque neighbourhood close to the sea.  edit
Oslo Hostel Rønningen YMCA, Myrerskogveien 54, Rønningen (Metro 5 or tram 11, 12 and 13 go to Storo, and from there bus 56 until Rønningen. Bus 56 only runs twice an hour, but every 20 minutes during rush hour), ? +47 21023600. checkin: 15-18. Open June 1 - August 19. 7.5 km from the center.  edit
Perminalen Hotell, Øvre Slottsgate 2 (T-bane to Stortinget, bus 30-31-32-54 to Wessels plass, tram 10-12-13-19 to Kongens gate). Perminalen offers slightly higher standards at slightly higher prices. OK cafe with good, old Norwegian homely grub at nice prices. Bed in 4-bed dorm: NOK 370; Single: NOK 620; Twin: NOK 840.  edit
Sentrum Pensjonat, Tollbugata 8, entrance from Skippergata (300 meters from Oslo Central station). Dorm bed: NOK 290; Single: NOK 500; Double: NOK 750. 

Hotels
Cochs Pensjonat, Parkveien 25 (tram 11 to Majorstua and 5 minutes walk or subway to Nationaltheatret and walk 10 minutes). Centrally located, next to the Royal Palace and Slottsparken. Three types of room to meet all budgets. They don't serve breakfast but have agreement with near cafe.  edit
Oslo Budget Hotel. The cheapest rooms require shared bathrooms. Single: 495 NOK; Double: 595 NOK.  edit
Thon Hotel Astoria, Dronningensgate 21 (50 metres from the main street Karl Johan, 5 minute walk from Oslo Central Station). Single: 695 NOK; Double: 895 NOK.  edit
Thon Hotel Munch, Munchs gate 5. A short walk to the main street, as well as easy walking distance to public transportation, airport shuttle bus and a vast variety of shops, restaurants, museums and theatres. Single: 695 NOK; Double: 895 NOK. 

Mid-range
Carlton Hotel, Parkveien 78 (near Aker Brygge). 50 rooms, small but good value. Restaurant with Japanese food.  edit
Radisson SAS Nydalen, Nydalesveien 33 (T Nydalen, 15 minute ride to center), ? +47-2326-3000. Choose from funky "Chilli" or more staid "Urban" rooms NOK 900+, breakfast included.  edit
Radisson SAS Plaza Hotel, Sonja Henies Plass 3. With 37 floors and breathtaking views of Oslo and the Oslo Fjord, the Radisson SAS Plaza Hotel is Northern Europe's highest and Norway's largest hotel. Suited 3 min walk from the train station. NOK 1300+.  edit
Thon Hotel Gyldenlove, Bogstadveien 20. Newly renovated hotel, with excellent location in Oslo's west quarter, right in the city's best shopping avenue, Bogstadveien.  edit
Thon Hotel Terminus, Stenersgaten 10 (downtown), .  edit
Thon Hotel Bristol, Kristian IV's gate 7 (right in the city centre, near the National Gallery and the main shopping street KarlJohansgate). As soon as you enter the lobby you will experience the unique style characterising the hotel. An air of elegance which have been maintained since the opening in 1920. From NOK 661.  edit

Splurge
Grand Hotel Oslo, Karl Johans Gate 31, ? +47 23 21 20 00, [130]. The hotel where Nobel Peace Prize winners stay when coming to Oslo for the award ceremony. Expensive and lots of services. Excellent view over main street Karl Johans gate. Grand Café, at street level, was Henrik Ibsen's daily watering hole, and is Norway's answer to Vienna's Cafe Landtmann. From NOK 2,175.  edit
Grims Grenka, Kongens gate 5, . Five star hotel which has received international acclaim. Operated by First hotels. Member of Design hotels.  edit
Hotel Continental Oslo, Stortingsgaten 24/26 (Located between the National Theatre and Aker Brygge), ? +47 22 82 40 00, . Family-run hotel has a large Vienna-style cafe (Theatercafeen) which is the place to be seen in Oslo. Outstanding service and prices to match, still considered fair value for money. Nice quiet bar with original Edvard Munch litographs.