泡沫经济，是指资产价值超越实体经济可承受的程度，使其极易丧失持续发展能力的宏观经济状态。泡沫经济经常由大量的投机活动所支撑。由于缺乏实体经济的支撑，因此其资产犹如泡沫一般容易破裂，因此经济学上称之为“泡沫经济”。

泡沫经济发展到一定的程度，经常会由于支撑投机活动的市场预期或者神话的破灭，而导致资产价值迅速下跌，这在经济学上被称为泡沫破裂。20世纪出现过多次泡沫经济浪潮，其中较为著名的是日本80年代广场协议引发的泡沫经济。其主要体现在房地产市场和股票交易市场等领域大幅投机炒作上涨达四年。但是一旦泡沫经济破裂，其影响将波及到一个国家的大多数产业甚至国际经济的走势。

A stock market bubble is a type of economic bubble taking place in stock markets when market participants drive stock prices above their value in relation to some system of stock valuation.

Behavioral finance theory attributes stock market bubbles to cognitive biases that lead to groupthink and herd behavior. Bubbles occur not only in real-world markets, with their inherent uncertainty and noise, but also in highly predictable experimental markets. In the laboratory, uncertainty is eliminated and calculating the expected returns should be a simple mathematical exercise, because participants are endowed with assets that are defined to have a finite lifespan and a known probability distribution of dividends. Other theoretical explanations of stock market bubbles have suggested that they are rational, intrinsic, and contagious.