The antonyms for "difference of opinion" can be unity, agreement, consensus, harmony, and concordance. Unity depicts a state where people have the same thoughts and beliefs about a situation. Agreement as the word implies, means people reaching a conclusion mutually. Consensus represents when everyone of a group agrees on a particular notion. Harmony indicates a pleasing combination of different elements, that is, when a particular thing is agreed upon by everyone harmoniously. Lastly, concordance is used to describe when people unanimously agree without any disagreements or opposing thoughts. These antonyms can be used to show solidarity and agreement in a discussion.