Toshikazu Kawaguchi is a Japanese novelist and playwright.
Born in Osaka in 1971, Kawaguchi began his literary career producing, writing, and directing for Sonic Snail, a theatrical group. That play became the source material for his debut novel, Before the Coffee Gets Cold, published in 2015. The novel won the grand prize at the 10th Suginami Drama Festival. Before the Coffee Gets Cold is the first novel in a series of three. The second novel in the series, Before We Say Goodbye was published in 2021, and the third, Before Your Memory Fades, was published in 2022. All three novels in the series have become international bestsellers and have led to a screen adaptation in Japan.