Title: Learning Invariant Features for Online Continual Learning. Abstract: It has been shown recently that learning only discriminative features that are sufficient to separate the classes in a task using a traditional learning method has a major shortcoming for continual learning (CL). This is because many features that are not learned may be necessary for distinguishing classes of some future tasks. When such a future task arrives, these features have to be learned by updating the network, which causes catastrophic forgetting (CF). A recent work on online CL showed that if the learning method can learn as many features as possible from each class, called holistic representations, CF can be significantly reduced to achieve a large performance gain. This paper argues that learning only holistic representations is still insufficient. The learned representations should also be invariant and those features that are present in the data but are irrelevant to the class (e.g., the background information) should be ignored for better generalization across tasks. This new condition further boosts the performance significantly. This paper proposes several strategies and a loss to learn holistic and invariant representations and evaluates their effectiveness in online CL.