〜てやる: Doing For (Down) / Defiant Determination
The downward charge it lays on the verb
You already know 〜てあげる ("do something for someone"). 〜てやる lays the same favor meaning onto a verb — but with a rougher, downward charge. The action is done for someone of lower or casually-equal status: animals, plants, younger family, close peers. Behind it sits the plain verb 〜をやる ("to give to someone/something below") — 花に水をやる ("water the plants") — and 〜てやる simply extends that "giving downward" from objects to actions:
毎朝、犬を散歩させてやる。
まいあさ、いぬを さんぽさせて やる。
Every morning I take the dog for a walk.
For a pet → てやる is natural.
ヤッタンは弟に漢字を教えてやった。
ヤッタンは おとうとに かんじを おしえて やった。
Yattan taught his little brother kanji.
弟 (younger) → downward favor.
モチが困っていたら、手伝ってやるよ。
モチが こまって いたら、てつだって やるよ。
If Mochi's in trouble, I'll help him out.
Casual peer; friendly but blunt.
Which verbs it rides on
Almost any action verb can carry it: take the て-form and attach やる. (Need a refresher? See the て-form.)
| Verb | て-form | + やる |
|---|---|---|
| 教える (teach) | 教えて | 教えてやる |
| 手伝う (help) | 手伝って | 手伝ってやる |
| 読む (read) | 読んで | 読んでやる |
| する (do) | して | してやる |
| 来る (come) | 来て | 来てやる |
The やる itself conjugates like a normal う-verb: やる → やった (past), やらない (negative), やろう (volitional).
The same shape, sharpened into resolve
Point that downward charge at your own goal and the auxiliary flips feeling entirely. When the action is about yourself, 〜てやる becomes a punchy, emotional "I'll do it — just watch me" — grit, a vow, sometimes spite. In this sense it overlaps with 〜てみせる ("I'll show you I can"):
今に見ていろ、絶対に成功してやる。
いまに みて いろ、ぜったいに せいこうして やる。
Just you wait — I'm going to succeed, no matter what.
Classic vow of determination.
あんな店、二度と行くものか。文句を言ってやる。
あんな みせ、にどと いく ものか。もんくを いって やる。
I'll never go to that shop again. I'm going to give them a piece of my mind.
言ってやる = defiant 'I'll tell them off.'
先生に勝ってやると、ヤッタンは心に決めた。
せんせいに かって やると、ヤッタンは こころに きめた。
'I'll beat the teacher,' Yattan resolved.
Inner resolve — not aimed at the teacher politely.
What tells the two senses apart is who benefits: if the action helps someone else (downward), it's a favor; if it's your own goal stated with force, it's determination.
Seeing both in context
子どもたちに本を読んでやるのが日課だ。
こどもたちに ほんを よんで やるのが にっかだ。
Reading books to the kids is part of my daily routine.
負けたままでは終われない。次は勝ってやる。
まけた ままでは おわれない。つぎは かって やる。
I can't end it on a loss. Next time, I'll win for sure.
モチが落ち込んでいたから、ごはんを作ってやった。
モチが おちこんで いたから、ごはんを つくって やった。
Mochi was feeling down, so I made him a meal.
Favor for a close friend — warm but rough register.
Set it against てあげる and てみせる
The plain verb and its neighbours mark where 〜てやる's edge lies:
- vs the neutral 〜てあげる. Even as a favor, 〜てやる keeps a top-down nuance, so it grates toward equals or superiors. 先生に教えてあげる is already a bit presumptuous — for a superior, drop the auxiliary and rephrase (e.g. お教えする). When you simply want to sound kind, that's 〜てあげる's job, not this one.
- vs 〜てみせる in the resolve sense. 手伝ってやる to someone else is a (blunt) favor; 成功してやる about yourself is determination — the subject and beneficiary decide, so don't let the identical shape blur them.
- It stays plain and rough. 〜てやる lives in casual, male-leaning speech and inner monologue. There is no natural polite "〜てやります" for the determination sense — that punchy feeling doesn't survive keigo, so keep it plain.
The short version
- 〜てやる = て-form + やる, with two senses.
- Favor (downward): for pets, plants, younger family, casual peers — the rough version of 〜てあげる.
- Determination/defiance: "I'll do it, just watch" — 絶対にやってやる.
- Past = 〜てやった; it's rough/plain, easily rude to equals or superiors.
Practice it
Decide whether each 〜てやる is a downward favor or a vow of determination, and whether てあげる would be safer.
＿＿＿に入れるのに最もよいものを選びなさい。
今に見ていろ、絶対に成功＿＿＿。
Frequently asked questions
What's the difference between 〜てやる and 〜てあげる?
Both mean doing something for someone, but 〜てやる is rougher and points downward — pets, plants, younger family, casual peers. 〜てあげる is the polite, neutral choice for friends, equals, and anyone you'd rather not sound condescending to.
How can the same 〜てやる mean both a favor and determination?
It's the beneficiary that decides. If the action helps someone else (downward), it's a favor: 手伝ってやる. If you state your own goal with force, it's determination: 絶対に勝ってやる ('I'll win, just watch').
Is 〜てやる rude?
It can be. Toward equals or superiors it sounds blunt or condescending. It's fine for pets, plants, young children, and close casual friends, and it's natural in tough-talk or inner resolve. When in doubt, use 〜てあげる.
Can I say 〜てやります politely?
For the favor sense it's possible but stiff and still top-down. For the determination sense, keep it plain (〜てやる) — that punchy, emotional feeling doesn't survive in polite form.
Where 〜てやる fits
Shaky on this? Get these solid first
- 〜てあげる · N5 — 〜てあげる means you do an action FOR someone as a favour, from the giver's side. Learn the て-form + あげる pattern, the に particle, the さしあげる/やる politeness levels, and the condescension trap.
- 〜てください · N5 — 〜てください is the standard way to politely ask someone to do something ('please do…'). Learn the formation, the negative 〜ないでください, softer variations, and see clear examples.
Don't confuse it with
- 〜てみせる · N3 — 〜てみせる has two senses: demonstrating something by actually doing it, and a strong vow ('I'll do it, just watch'). Learn formation, both meanings, and てみる vs てみせる.
Once this clicks, go on to
- 〜てあげる · N5 — 〜てあげる means you do an action FOR someone as a favour, from the giver's side. Learn the て-form + あげる pattern, the に particle, the さしあげる/やる politeness levels, and the condescension trap.
More N3 grammar to explore
Keep going with related patterns at the same level:
- 〜をはじめ — 〜をはじめ(として) names the leading example of a larger group: 日本をはじめ、アジアで人気. Learn the formation, the adnominal 〜をはじめとする, register, and common mistakes.
- 〜ばいい / 〜たらいい — 〜ばいい and 〜たらいい give advice ('you should / just have to') or express hope ('I hope it...'). Learn どうすればいい, 〜たらいいな, and how ばよかった differs.
- 〜べき — 〜べきだ means 'should' or 'ought to' — a strong, principled obligation. Learn how to form it, すべき vs するべき, the negative べきではない, and the regretful べきだった.
- 〜ことはない — 〜ことはない attaches to a dictionary-form verb to say there's no need or no reason to do something — reassurance and advice. Learn the form, the polite ことはありません, and how it differs from 〜ないことはない and なくてもいい.
- 〜ば〜ほど — 〜ば〜ほど means 'the more X, the more Y.' Learn how to repeat verbs and adjectives in the ば-form + dictionary/plain + ほど pattern, with な-adjective and noun forms.
- 〜ばよかった — 〜ばよかった expresses regret about something you didn't do: もっと早く出ればよかった ('I should have left earlier'). Learn the form, the なければよかった negative, and 〜てよかった.