MikuMikuDance (commonly abbreviated to MMD) is a freeware animation program that lets users animate and create computer-animated films, originally produced for the Japanese Vocaloid voice synthesizer software voicebank Hatsune Miku, the first member of the Character Vocal series created by Crypton Future Media.

[3] The software allows users to import computer-generated models into a virtual space that can be moved and animated accordingly.

Along with these functions for models, accessories, stages, and backgrounds can be added to create an environment, and effects such as lens flares and AutoLuminous (an effect that makes things glow and light up) can be applied as long as the MikuMikuEffect (MME) plugin is installed into the interface.

The creator, HiguchiM, has stated he can make no promises regarding how other users' fan-made models can or cannot be used, and is exempt from all responsibility relating to this subject.

[4] Videos using the software are regularly seen on sites such as Niconico and YouTube and are popular among Vocaloid fans and users alike.

[7] Despite this, the source code has not been released, and the developer has no intentions of doing so, making it impossible for people to continue building upon the original software.

However, there are alternative programs that provide similar functionality, such as MikuMikuMoving (MMD's "replacement" that is updated frequently and has many of the features of MMD, as well as new file formats unique to the program, support for the Oculus Rift head-mounted display and a new UI, among other features),[8] and the free software, Blender.

The models of the Vocaloids provided with the software are subject to Piapro Studio's Character License, and are not allowed to be used without permission for commercial reasons.

The program does not include all of the Vocaloids by default, but it includes Crypton Future Media's Vocaloids which are Hatsune Miku, Kagamine Rin, Kagamine Len, KAITO, MEIKO, and Megurine Luka; and although Yowane Haku, Akita Neru, Sakine Meiko, and Kasane Teto are not official Vocaloids (Teto being both an UTAU and a vocal synth for Synthesizer V), they became so popular that Crypton Future Media officially licensed and added them to Hatsune Miku: Project DIVA.