おかげで (or お陰（かげ）で in kanji) is an expression that is used to show thanks or appreciation in Japanese. It is usually translated simply as ‘thanks to (A)’, or ‘because of (A)’. おかげで is a combination of the polite prefix お, the 名詞（めいし） (noun) 陰（かげ） ‘shade’, and the 格助詞（かくじょし） で.
おかげで can be used after any word in its 連体形（れんたいけい） (attributive form).
-
タケルくんに手伝（てつだ）ってもらったお陰（かげ）で仕事（しごと）が早（はや）く終（お）わったよ。今日（きょう）は本当（ほんとう）にありがとうね。
We were able to finish work early, thanks to you helping us Takeru. Thank you so much for today.
部屋（へや）が汚（きたな）いお陰（かげ）でどこに何（なに）があるか全（まった）く分（わ）からない。
Thanks to my room being so dirty, I don't know where anything is. (Sarcasm)
友達（ともだち）が有名（ゆうめい）なおかげで、どんな高級（こうきゅう）レストランでも予約（よやく）なしで入（はい）れる。
Thanks to my friend being famous, we can go to any fancy restaurant without a reservation.
あなたのおかげで不自由（ふじゆう）のない生活（せいかつ）ができている。
Thanks to you, we can live a life free of inconvenience.
Literally, お陰（かげ）で means ‘in the shade of (A)’. This implies that (B) was only made possible due to (A) creating the ideal situation for it to occur.
おかげで may sometimes be used sarcastically, in the same way as ‘thanks to (A)’ in English. In these sentences, it is usually quite clear from the context/tone of voice that the actual meaning is negative.
-
お前（まえ）が変（へん）な事（こと）言（い）ったおかげで、俺（おれ）が言（い）いたい事（こと）を忘（わす）れちゃったじゃん！
Thanks to you saying something weird, I forgot what I wanted to say! (Sarcasm)
あいつのおかげでまた残業（ざんぎょう）だよ。
We have to work overtime again thanks to him. (Sarcasm)
おかげで is often used at the beginning of a sentence in the same way as ‘thankfully’ or ‘luckily’ in English. This just means that whatever comes after おかげで happened, despite negative outcomes also being possible.
-
おかげで、テストに合格（ごうかく）することができました。
Thankfully, I was able to pass my test.
おかげで、いい休暇（きゅうか）を過（す）ごせました。
Thanks to you, I was able to enjoy a nice holiday.