- Acknowledgement vs. acknowledgment
- Aeon vs. eon
- Aeroplane vs. airplane
- Afterward vs. afterwards
- Ageing vs. aging
- Agree
- All-around, all-round
- Aluminium vs. aluminum
- Among vs. amongst
- Analyse vs. analyze
- Annex vs. annexe
- Apologise vs. apologize
- Appal vs. appall
- Armor vs. armour
- Arse vs. ass
- Authorise vs. authorize
- Autumn vs. fall
- Ax vs. axe
- Beggar belief
- Behavior vs. behaviour
- Bulk, balk, baulk
- Burgle vs. burglarize
- Burned vs. burnt
- Caliber vs. calibre
- Canceled vs. cancelled
- Catalog vs. catalogue
- Center vs. centre
- Check vs. cheque
- College vs. university
- Color vs. colour
- Cooperate vs. co-operate
- Costed
- Cosy vs. cozy
- Counselor vs. counsellor
- Crayfish, crawfish, crawdad, etc.
- Curb vs. kerb
- Customise vs. customize
- Defence vs. defense
- Different from, different than, different to
- Dike vs. dyke
- Draft vs. draught
- Dreamed vs. dreamt
- Endeavor vs. endeavour
- Enrol vs. enroll
- Farther vs. further
- Favor vs. favour
- Favorite vs. favourite
- Fiber vs. fibre
- First floor
- Flautist vs. flutist
- Flavor vs. flavour
- Flier vs. flyer
- Fueled/fueling vs. fuelled/fuelling
- Fulfil vs. fulfill
- Full stop vs. period
- Furor vs. furore
- Gaveled vs. gavelled
- Glamour vs. glamor
- Got vs. gotten
- Gray vs. grey
- Harbor vs. harbour
- Hoover vs. vacuum
- Humor vs. humour
- Impinge vs. infringe
- Installment vs. instalment
- Jewelry vs. jewellery
- Kick off vs. kickoff (vs. kick-off)
- Labeled vs. labelled
- Labor vs. labour
- Lambast vs. lambaste
- Lasagna vs. lasagne
- Leaped vs. leapt
- Learned vs. learnt
- Licence vs. license
- Licorice vs. liquorice
- Lieutenant
- Likable vs. likeable
- Liter vs. litre
- Lorry
- Maneuver vs. manoeuvre
- Math vs. maths
- Meager vs. meagre
- Meter vs. metre
- Modeling vs. modelling
- Mold vs. mould
- Mollusc vs. mollusk
- Molt vs. moult
- Neighbor vs. neighbour
- Ocher vs. ochre
- Odor vs. odour
- Offence vs. offense
- Omelet vs. omelette
- One-time vs. onetime
- Organise vs. organize
- Ouster
- Pajamas vs. pyjamas
- Paralyse vs. paralyze
- Percent vs. per cent
- Phony vs. phoney
- Plough vs. plow
- Practice vs. practise
- Pretence vs. pretense
- Program vs. programme
- Realise vs. realize
- Rumor vs. rumour
- Sanitise vs sanitize
- Savanna vs. savannah
- Savior vs. saviour
- Sceptic vs. skeptic
- Skilful vs. skillful
- Smelled vs. smelt
- Somber vs. sombre
- Specter vs. spectre
- Spelled vs. spelt
- Spilled vs. spilt
- Spoiled vs. spoilt
- Sulfur vs. sulphur
- Takeaway and takeout
- Theater vs. theatre
- Tidbit vs. titbit
- Tire vs. tyre
- Ton vs. tonne
- Totaled/totaling vs. totalled/totalling
- Toward vs. towards
- Transport vs. transportation
- Traveled/traveling vs. travelled/travelling
- Treasurys
- Tunneled, tunneling vs. tunnelled, tunnelling
- Wagon vs. waggon
- Wilful vs. willful
- Woolen vs. woollen
- Yoghurt vs. yogurt
- Zee vs. zed
