To see a koala in your dream, represents your link the physical world, the unconscious, and the spiritual realm. The koala also symbolizes security, nurturance, protection, and/or feminine qualities. You may be expressing a desire to regress back into infantile dependence and escape from your daily responsibilities/problems.
Locations or cultures where koalas live
Living "above" others, perhaps with a greater perspective (since koalas live in trees)
Isolation from others
Cute, infant-like, or toy-like
Gentleness
Dreaming of this animal can represent:
Having too much of one of these qualities, or that you could benefit by being less this way
Not having enough of one of these qualities, or that you could benefit by being more like this
Someone or something in your real life with whom you associate one of these qualities (an event, situation, threat, etc.)
For more clues, pay attention to what the animal was doing or any particular characteristic that stood out.