Electoral violence often perpetrated by political party vigilante groups in Ghana has been a major setback to Ghana’s drive towards democratic maturity. In particular, acts and incidence of violence have been alarming during parliamentary by-elections at the constituency level, which have often led to major casualties like deaths, injuries, destruction of property, inter-party conflicts, as well as social and communal tensions. Yet, very little attention has been given to electoral violence and vigilantism during parliamentary bye-elections. This study fills this gap by drawing on interviews, general observations, and archival sources to examine the causative factors for the persistence of parliamentary by-election violence, at the constituency level. The central questions addressed in the paper are: what is the motivation for the involvement of political party vigilante groups in parliamentary by-elections and associated conflicts?; what strategies do political parties use to mobilize vigilante groups during parliamentary bye-elections; and what are the implications of parliamentary by-election conflicts for inter-party and communal relations, at the constituency level? The study concludes on the note that, the stakes are often high in the conduct of bye-elections, as the whole concentration of the nation is deployed to small constituencies where such elections are held, culminating in a more pronounced activities of vigilante groups in such communities, during by-elections. It finally raises the question with regards to how to manage the rising incidence of vigilante group activities in the conduct of bye-elections, and suggests this, as being the focus of any future research activity on political vigilantism in Ghana.