意思不同、用法不同、后接宾语不同。agree on是对某事（物）有同样看法，商定（同意）某事或商定做某事。agree to是同意，赞成，同意照办（说明）通常不用于进行体。agree with是与某人（某观点）一致，同意，赞同某人的意见（说明），通常不用于进行体，也不用于被动结构。
“agree to sth（建议）”表示“赞同某人的建议”
注意和第一一点的区别，这里的to，是个介词，故而后面跟名词或者代词。
Miss White didn't agree to his suggestion.怀特小姐不同意他的建议。
“agree with sb ”表示“赞同某人的观点”
注意with后跟人，表示赞同某人的看法。agree后面跟to和with的用法是初中英语必考的一个知识点，记住介词to后面是“事”；介词with后面是“人”。
I don't agree with you.你的看法，我不敢苟同。
Gentlemen get along with others；but do not necessarily agree with them.君子和而不同。
“agree on sth（决定）”表示“赞成某人的决定”
We all agreed on his decision.我妹妹都同意了他的决定。
agree with，agree to，agree on的区别和用法：
1、agree with sb 意为“适合(某人的健康或胃口)”，尤用于否定句或疑问句中。
agree with sb . 表示“同意某人的意见”。 agree with sb. 意为“同意某人”。
2、agree (to sth) 意为“同意;愿意;答应(某事物)”。
3、be agreed(on /about sth)意为“达成协议;意见一致”。
拓展资料
agree with
1、I quite agree with you. That's a good way of looking at it.
我很赞同你的观点，这是看待该问题的一个很好的角度。
2、No, I'm sorry, I can't agree with you
不，很抱歉，我不同意你的看法。
3、Changes are being made here which go against my principles and I cannot agree with them.
这里作的改动违背了我的原则，我不能同意。
4、I don't agree with you at all.
我压根儿就不赞成你的主张。
5、I agree with you that the open system is by far the best
我同意你的观点，开放的系统显然是最佳的。
agree to
1、I cannot but agree to your decision.
我不得不同意你的决定。
2、You and I are going to have to agree to disagree then.
那你我只能各自保留不同意见了。
3、He said all that remained was to agree to a time and venue
他说剩下的只是商定一个时间和集会地点。
4、The management is understood to be very unwilling to agree to this request
据了解，管理层很不乐意答应这项要求。
5、I fully agree to the arrangement and take delight in it [ take it with delight].
我完全赞成并乐于接受这一安排。
agree on
1、Both approaches agree on what is depicted in the poem, but not on how it should be interpreted.
两种方法对诗中所描绘的是何种事物的看法是一致的，但是对于应该如何阐释这首诗有所分歧。
2、They agree on fundamentals, like the need for further political reform.
他们在需要深化政治改革等基本问题上意见一致。
3、The two sides failed to agree on the wording of a final report
双方未能就最终报告的措辞达成一致。
4、'I think we could agree on that one.' — 'Only just.'
“我想在那一点上我们是一致的。”——“勉强算是吧。”
5、The other two opposition parties cannot agree on an electoral pact between themselves.
另外两个反对党之间无法就选举达成协议。