A collapsible acoustic stringed instrument is disclosed having a hollow body with a soundboard, a back face and a spacer defining a sound chamber. A sound post is secured within the hollow body and engaging the soundboard and the back face. The sound post has a securement pin on each end with a sharpened portion to engage the soundboard and the back face and maintain proper positioning when the instrument strings are loosened. A neck is pivotally and laterally coupled to the body, which further has a door slidably received by specially formed channels in the back face. The neck is able to pivot and slide through the door and into the sound chamber from a playing position to a stored position, without disturbing the sound post or otherwise compromising the appearance or performance of the instrument with respect to a standard non-collapsible instrument.