Mmanwu // ^ⓘ is a traditional masquerade of the Igbo people of Southeastern Nigeria. They are performed only by males in exclusive secret societies and involve the use of elaborate, colorful costumes that are meant to invoke ancestral spirits. Masquerade traditions have a varied range of purposes that span from performing elements of epic drama derived from community cosmology and lore, ushering in new months and seasons, honoring totems and ancestral spirits, enactments of parables or myths, with entertainment and community building serving as a consistent commonality. In the past masquerades also bore judicial, social regulatory, and even policing powers, however though these functions have decreased in modern times.

The word "Mmanwu" in Igbo means "spirits of the dead". It is the combination of two Igbo words "mmuo" or "maa" which means spirit and "onwu" which means death. This refers to the purpose behind Mmanwu which is to create physical representations of spirits and ancestors through the adornment of the masks.

The visible masquerades are meant for the public. They often are more entertaining. Masks used offer a visually appeal for their shapes and forms. In these visual masquerades, performances of harassment, music, dance, and parodies are acted out (Oyeneke 25). These dramatic performances often depict stories of daily life with a moralistic bent that highlights the social norms that the Mmanwu so closely enforce. The local instruments used in these depictions are integral to the spiritual intention of the stories and the actual masks themselves include a great deal of artistic drama. It has been argued that this has been the most resilient type of Mmanwu since the others have sometimes lost prominence with changing social institutions and structures. Ceremonial Mmanwu has even been incorporated into other religious celebrations such as the inclusion of Mmanwu in Igbo Christmas and Easter parades.

The invisible masquerades take place at night. Sound is the main tool for them. The masquerader uses his voice to scream so it may be heard throughout the village. The masks used are usually fierce looking and their interpretation is only fully understood by the society members. These invisible masquerades call upon a silent village to strike fear in the hearts of those not initiated into their society. The invisible masquerades can be broken down into three groups, achikwu ocha/ojii, agu mmuno, and ogbagu.

The achikwu ocha (white) masquerade acts as village surveillance. The "entertainment" activities include "singing, joking, and dancing" (Oyeneke 22). Achikwu ojii (black) is the other side of the achikwu ocha masquerade. This is performed not only to protect the village, but also when there is going to be a punishment or execution of a criminal

Mmanwu is a way for Igbo people to regulate and discipline members of their society. Mmanwu will work alongside the Igbo community's political assembly, often stepping into action when the political assembly has reached a stalemate in a certain issue. They work to execute pre-determined and long-standing social norms, often using symbolic messaging. One example of this comes from an interview Bess Reed held with an Igbo woman. The woman discusses how after she complained to prominent members of her community about stolen mangos from her tree, the Mmanwu marked her mango tree overnight with fresh palm leaves and no thievery occurred thereafter. The Mmanwu is a salient example of an informal organization.

The second group of invisible masquerades is agu mmuno (leopard spirit). In these masquerades, horrible screaming sounds are produced to create fear.

This third category is "strictly used for dance entertainment" (Oyeneke 22).