A flag symbolizes the union between feminine and masculine.
The pole is an obvious erect phallic symbol while at the same time the flag fabric itself represent the feminine, symbolizing the material of the mother and of woman.
In dreams, as well as in waking life, the flag can also represent a totality; just as it represents all the men and women of a particular nation, in dreams it represents the inner life as a whole – emotions and creativity, attraction and power.
A flag is a symbol that unites a group of people, so if you dream about a flag, it can mean that you are hoping that other people in your life share your values and your goals.
You may feel that someone that you are close to is behaving in a way that you consider unacceptable, or you may feel that you are not getting enough support for a project that you have undertaken.
If you dream of people waving flags in a crowd, your dream can mean that you feel that you are being pressured to behave in a certain way.
You may also feel that people around you are acting without thinking, or that they are trying too hard to conform.
If you dream about the flag of a particular country, the meaning of your dream will have to do with the feelings that you have about that country.