As one wishes; as expected; the way one wants (often used adverbially with 〜に).
予定は思い通りに進まなかった。
Things didn't go as planned.
子どもは思い通りにおもちゃで遊んでいる。
The child is playing with the toy as he pleases.
仕事は必ずしも思い通りにならないこともある。
Work doesn't always go the way you want.
思い通りにいって嬉しい。
I'm happy that it went my way.