There are a total of 169 8-letter words containing 'tion', and the number may vary in different dictionaries. You can specify the dictionary and order.

• ablation ₁₃
• ablution ₁₄
• abortion ₁₂
• actioned ₁₃
• actioner ₁₂
• adaption ₁₃
• addition ₁₁
• adnation ₁₁
• adoption ₁₃
• aeration ₉
• agnation ₁₂
• alations ₁₀
• ambition ₁₅
• amotions ₁₂
• auctions ₁₃
• audition ₁₁
• aviation ₁₃
• bastions ₁₂
• captions ₁₅
• cationic ₁₅
• cautions ₁₃
• citation ₁₂
• coaction ₁₅
• coitions ₁₂
• conation ₁₃
• cooption ₁₅
• creation ₁₂
• curation ₁₃
• delation ₁₁
• deletion ₁₁
• demotion ₁₃
• deration ₁₀
• devotion ₁₄
• dictions ₁₃
• dilation ₁₁
• dilution ₁₂
• donation ₁₁
• dotation ₁₀
• duration ₁₁
• editions ₁₀
• eduction ₁₄
• egestion ₁₁
• ejection ₂₁
• elations ₁₀
• election ₁₃
• elutions ₁₁
• emotions ₁₂
• enaction ₁₃
• enations ₁₀
• equation ₁₉
• erection ₁₂
• eruption ₁₃
• evection ₁₆
• eviction ₁₆
• exaction ₁₉
• exertion ₁₆
• factions ₁₅
• fetation ₁₂
• fictions ₁₅
• fixation ₁₉
• flection ₁₆
• fraction ₁₅
• friction ₁₅
• fruition ₁₃
• function ₁₇
• gelation ₁₂
• gumption ₁₈
• gyration ₁₃
• halation ₁₂
• himation ₁₄
• ideation ₁₀
• ignition ₁₂
• illation ₁₁
• inaction ₁₃
• iodation ₁₀
• junction ₂₃
• lavation ₁₄
• laxation ₁₇
• lections ₁₃
• legation ₁₂
• lenition ₁₁
• libation ₁₃
• ligation ₁₂
• lobation ₁₃
• location ₁₃
• locution ₁₄
• lunation ₁₂
• luxation ₁₈
• mentions ₁₃
• monition ₁₃
• motional ₁₃
• motioned ₁₃
• motioner ₁₂
• munition ₁₄
• mutation ₁₃
• natation ₁₀
• national ₁₁
• negation ₁₂
• nidation ₁₁
• nivation ₁₄
• nolition ₁₁
• notation ₁₀
• notional ₁₁
• novation ₁₄
• nutation ₁₁
• oblation ₁₃
• optional ₁₃
• optioned ₁₃
• optionee ₁₂
• orations ₉
• ovations ₁₃
• pactions ₁₅
• petition ₁₂
• portions ₁₂
• position ₁₂
• potation ₁₂
• punition ₁₄
• pupation ₁₆
• question ₁₉
• rational ₁₀
• rationed ₁₀
• reaction ₁₂
• relation ₁₀
• remotion ₁₂
• rogation ₁₁
• rotation ₉
• ructions ₁₃
• sanction ₁₃
• sections ₁₂
• sedation ₁₀
• sedition ₁₀
• solation ₁₀
• solution ₁₁
• sorption ₁₂
• stations ₉
• stiction ₁₂
• suctions ₁₃
• sudation ₁₁
• swaption ₁₅
• tactions ₁₂
• taxation ₁₆
• traction ₁₂
• tuitions ₁₀
• unctions ₁₄
• vacation ₁₆
• venation ₁₄
• vexation ₂₀
• vocation ₁₆
• volition ₁₄
• volution ₁₅
• zonation ₁₉
• amations ₁₀
• bibation ₁₂
• cantions ₁₀
• cibation ₁₂
• coctions ₁₂
• emiction ₁₂
• emptions ₁₂
• inustion ₈
• jobation ₁₇
• limation ₁₀
• mictions ₁₂
• mixtions ₁₇
• nodation ₉
• nudation ₉
• pacation ₁₂
• rections ₁₀
• scontion ₁₀
• unitions ₈

There are 169 8-letter words containing tion in the well-known word game dictionary, 148 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 168 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 151 in the Words with Friends (WWF) dictionary.