A modular automated assistive guitar is described comprising a base assembly, a pick assembly, a strumming mechanism and a fretting mechanism which, in combination with a standard guitar or similar stringed musical instrument (e.g., banjo, steel guitar, ukulele), forms a musical device that can be played by an individual with a range of independence, cognitive and physical abilities. The base assembly accepts, positions, and secures a standard guitar. The pick assembly includes quick attach and spring-loaded features for attaching and detaching picks, in addition to flexibility for smooth interaction with the guitar strings. The strumming mechanism provides cyclic motion and speed control to create pleasant and variable rhythm from the mounted guitar. The fretting mechanism allows a user to change chords and tone. An unmodified, traditional guitar is preferably used in the musical device. The guitar is easily interchangeable with another guitar or other stringed instrument, at the convenience of the user. The modular automated assistive musical device, with or without the guitar, is compact, light, portable, and easily adjustable to different individual's needs, motor skills, and dexterity.