のももっともだIt is understandable that...
This pattern says that a person's feeling, complaint, decision, or other response is reasonable in light of the circumstances. It recognizes the person's reasons, but does not necessarily mean that the speaker agrees with every conclusion they reach.
What it evaluates
The clause before の presents the response being evaluated. The construction works best when the surrounding sentence makes the person's reasons clear: difficult circumstances, unfair treatment, missing information, repeated problems, or another understandable basis for the response.
A response supported by clear circumstances
彼は三か月も休みなしで働いたのだから、辞めたいと思うのももっともだ。
He has worked for three months without a break, so it is understandable that he wants to quit.
AnalyzeUnderstanding is not full agreement
This pattern can validate a person's reaction while leaving room to question what they plan to do about it. That makes it useful when you want to sound fair rather than simply approve or disapprove.
彼が慎重になるのももっともだが、計画を中止する必要まではない。
It is understandable that he would become cautious, but there is no need to cancel the plan.
AnalyzeThe speaker accepts the caution as reasonable without accepting cancellation as necessary.
In conversation
佐藤さん、異動を断ったそうです。
I hear Sato turned down the transfer.
Analyze家族の介護があるなら、断るのももっともですね。
If Sato has a family member to care for, turning it down is understandable.
AnalyzeThe sentence-ending particle softens the assessment and makes it sound naturally conversational.
Two important distinctions
もっともだ evaluates a response or position as reasonable. By contrast, 当然だ more directly presents something as natural, expected, deserved, or due. Also keep this pattern separate from sentence-linking もっとも, which accepts a point and then adds a reservation.
本人が規則を破ったのだから、処分を受けるのも当然だ。
Since the person broke the rule, it is only natural that they face disciplinary action.
AnalyzeThis presents the consequence as due rather than empathetically assessing a person's reaction.
More examples
初めての海外生活で不安になるのももっともだ。
It is understandable to feel anxious when living abroad for the first time.
Analyzeこれだけ説明が曖昧なら、参加者が戸惑うのももっともです。
With an explanation this vague, it is understandable that the participants are confused.
Analyze長年支えてきた企画が突然打ち切られ、彼女が落胆したのももっともだ。
The project she had supported for years was suddenly terminated, so it is understandable that she was disappointed.
Analyze十分な情報がないのだから、彼女がすぐには決められないのももっともだ。
Since she does not have enough information, it is understandable that she cannot decide immediately.
Analyze情報がほとんどないのだから、担当者が慎重なのももっともだ。
Since there is almost no information, it is understandable that the person in charge is cautious.
Analyze条件が以前と大きく違う以上、組合が再交渉を求めるのももっともだ。
Given that the conditions are substantially different from before, it is understandable that the union is asking for new negotiations.
Analyze