William Tapia (January 1, 1908 – December 2, 2011), known as "Uncle Bill" and "Tappy", was an American musician, born to Portuguese parents.

At age 8, Tapia was already a professional musician, playing "Stars and Stripes Forever" for World War I troops in Hawaii.

In his long career beginning in vaudeville and quickly expanding as a jazz guitarist and ukulele player he performed with names such as Bing Crosby, Louis Armstrong, Elvis Presley and Hawaiian musicians such as King Bennie Nawahi, Sol Hoʻopiʻi, and Andy Iona.

On March 23, 2004, he provided a detailed interview for the NAMM Oral History Program collection about his impressive career and life in music.

He continued to perform and record at an advanced age, all the while remaining in vigorous health and driving a car until his 100th birthday when he began suffering eyesight problems.