Dreaming of uniforms is most often a dream of self-awareness. Conformity through clothing is one of the unspoken rules of culture and we often perceive parts of our wardrobes as our "uniform" for particular roles we fill in life. In dreams of uniforms, it does not matter if the uniform is officially recognized or simply identical clothing on numerous persons.
If you are in uniform, and there are others dressed the same way, consider who is with you in the dream and what camaraderie you share with them. It may be that you are recalling a satisfying tenure in military service, employment, or identity with a particular group. If you are in uniform and others are not, it may reflect a feeling that you perceive yourself as more loyal than others.
A 24-year-old man reports dreaming: I am in the Navy. They have not trained me. I report to my ship with my only uniform, which is summer whites. Everyone around me is in dress blues. Nothing on the ship goes right.
This dreamer, a college student, was contemplating an officer's commission in the navy. He was excited, but hedging his commitment. This dream reflected those concerns and warned him to examine the situation more closely.
Uniforms can also be a symbol of authority. Note the person wearing a uniform in your dream. Was it a logical situation for that person to be wearing a uniform?