How to say "mutually" in Japanese

• 互いにたがいにCommon
  adverbCovers 'mutually', 'with each other', 'reciprocally', 'together': an action or feeling that two people or sides exchange, as in helping, respecting, or understanding each other. This is the bare form, without the polite prefix.
  私達わたしたちは互たがいに依存いぞんしあっている。↗

  We are dependent on each other.
• お互いにおたがいにCommon
  adverbThe full range of senses — mutually, with each other, reciprocally, together — with the polite prefix お lending a softer, more courteous tone; choose it when politeness is called for.
  ジョンとメアリーはお互たがいに愛し合あいしあっていました。↗

  John and Mary loved each other.

「互いに」 and 「お互いに」 share the same senses — mutually, with each other, reciprocally, together — so the choice is one of tone: bare 「互いに」 for plain statements, 「お互いに」 when the polite お prefix is wanted.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 互いにたがいにmutually
• お互いにおたがいにmutually
• 相あいtogether
• 互にかたみにmutually