What determines the behaviour of the security arm of the state in ethnically plural societies? Various hypotheses have been developed to arrive at an explanation. Two popular hypotheses are the emboldenment hypothesis and the instability hypothesis. The first assumes that in plural states, whenever the security arm is dominated by the same ethnic group that dominates the executive arm of government, members of the security force become emboldened and engage in acts which threaten the security of outgroups. The second posits that when there is a difference in ethnicity between the executive arm and the security arm, the actions of the security forces threaten the political stability of the state. This chapter engages these two hypotheses in the context of Guyana, a plural society that has experienced both structural configurations. Both hypotheses are tested around the assumptions of an ethnic security dilemma. Using the Latin American Public Opinion Project dataset, this chapter examines the hypotheses empirically and discusses the findings with respect to ethnic relations in Guyana. The evidence seems to contradict the two hypotheses and underscores the need for more in-depth research on ethnicity and security in ethnically plural societies.