Using a sentiment measure constructed from cryptocurrency-related posts on social media, we examine whether investor sentiment affects the prices of cryptocurrency options. We find that Bitcoin options exhibit a volatility smile, which becomes steeper when sentiment becomes more bearish. The risk-neutral skewness of Bitcoin returns implied by option prices tends to be more negative in times of more bearish sentiment. The sentiment effect is pronounced when Bitcoin appreciates and attracts high investor attention and arbitrage in Bitcoin options is more limited. These findings are robust to controlling for momentum, volatility, and demand pressure. We find similar results for Ethereum options.