"Bullying" has a number of definitions, but most contain the five key elements described by Farrington (1993): physical, verbal, or psychological attack; an imbalance of power; repetitive; unprovoked; and intended to cause fear or harm to the victim. There are a number of problems in applying current definitions of bullying to an incarcerated sample, however. Use of the term, which is considered derogatory, encourages underreporting, which means that no accurate estimate of the extent of bullying can be obtained. This means that any findings drawn from prison studies of bullying must be interpreted with caution. The concept of dominance is of primary importance when describing bullying between prisoners. Dominance is an encouraged element of imprisonment, with victims likely to remain isolated from the rest of the prison population. The prison subculture's emphasis on dominance and taboo against inmates reporting on other inmates gives victims of bullying no means of escape from the abusive interaction. The inmate subculture may accentuate their victimization by enforcing sanctions against reporting to prison officials. In the United Kingdom, bullying in prison has long been recognized as a serious problem, having been implicated in the suicides of four young offenders during 1991 and 1992 in one prison alone. Victims are most likely offenders with little prison experience. Although studies of bully characteristics are sparse, findings to date suggest that bullies are slightly younger than victims and had previously been in custody. Research limitations are discussed in this article, along with directions for future research. 64 references