Johann Jakob Walder (born 1740, date of death unknown) was a Swiss composer and violinist, primarily active during the Classical period. He is best known for his contributions to chamber music, particularly for string instruments. Walder's works often reflect the stylistic transitions of the time, blending elements of Baroque intricacy with the emerging clarity and balance of Classical forms. Among his notable works are a series of string quartets and various sonatas for violin and piano, which showcase his melodic inventiveness and mastery of counterpoint. His compositions were published in the late 18th century, helping to establish his reputation in the realm of chamber music. Although not as widely recognized as contemporaries like Haydn or Mozart, Walder's music is important for its contribution to the development of the string quartet genre and for influencing later composers in the Swiss musical tradition. His works continue to be of interest to performers and musicologists exploring the evolution of Classical music in Switzerland.