To dream of a rat often indicates anxiety or upset in the dreamer's waking life. Many human beings are naturally afraid of rats and consider them filthy pests that create a negative environment. If the dreamer's waking environment is particularly stressful or negative, one or more rats appearing in his dreams can point to the lack of control the dreamer feels in his daily life.
Alternatively, dreaming about rats also represents survival as rats are known to survive harsh elements and unsavory living conditions. If the dreamer is facing a particular challenge in his waking life, and a rat appears in his dream, this often depicts a feeling of inner strength and a will to survive.
Rats also represent unethical and deceitful people, and they can appear in dreams as symbols of a deceitful person in the dreamer's waking life. It is always a good idea for the dreamer to journal his dreams upon waking in order to analyze them at a later time or if the dream recurs.
Additionally, guilt is another factor when dreaming about rats. If the dreamer has been dishonest or deceitful, his subconscious reminds him of this fact with the appearance of a rat. Dishonest and sneaky people are often referred to as "rats."