Spurred by advancements in scale, large language models (LLMs)  have demonstrated the ability to perform a variety of natural language processing (NLP)  tasks zero-shot—i.e., without adaptation on downstream data. Recently, the debut of ChatGPT111https://chat.openai.com/has drawn a great deal of attention from the natural language processing (NLP)  community due to the fact that it can generate high-quality responses to human input and self-correct previous mistakes based on subsequent conversations. However, it is not yet known whether ChatGPT can serve as a generalist model that can perform many NLP tasks zero-shot. In this work, we empirically analyze the zero-shot learning ability of ChatGPT by evaluating it on 20 popular NLP datasets covering 7 representative task categories. With extensive empirical studies, we demonstrate both the effectiveness and limitations of the current version of ChatGPT. We find that ChatGPT performs well on many tasks favoring reasoning capabilities (e.g.,arithmetic reasoning)  while it still faces challenges when solving specific tasks such as sequence tagging. We additionally provide in-depth analysis through qualitative case studies.