Siddhartha is an allegorical novel by Hermann Hesse that deals with the spiritual journey of a boy known as Siddhartha from Nepal during the time of the Buddha.

The book, Hesse's ninth novel, was written in German, in a simple yet powerful and lyrical style. It was first published in 1922, after Hesse had spent some time in India in the 1910s. It was published in the U.S. in 1951 and became influential during the 1960s. Hesse dedicated Siddhartha to Romain Rolland, "my dear friend".

The word Siddhartha is made up of two words in the Sanskrit language, siddha (achieved) + artha (meaning or wealth). The two words together mean "he who has found meaning (of existence)" or "he who has attained his goals". The Buddha's name, before his renunciation, was Prince Siddhartha Gautama. In this book, the Buddha is referred to as "Gotama".