In this paper we present an overview of studies of the mechanisms of emotional Stroop effect. Emotional Stroop effect is one of the possible ways to demonstrate emotional information processing. It is a delay in naming the color of emotional stimuli, compared to that of neutral stimuli. Two main approaches explain the origins of this delay, viewing emotional Stroop effect as a fast and a slow effect. The fast-effect explanation suggests that the delay emerges during the current task, when a large amount of attentional resources is used to process the emotional information. The slow-effect approach proposes that the delay does not originate immediately and only becomes evident in subsequent tasks, which can be explained by difficulties in diverting attention away from emotional information or by a mechanism of general reaction inhibition in response to threat detection. There are empirical findings in support for both interpretations, which suggests that both mechanisms may exist. Some studies show that the effect is composite and it includes two components, fast and slow. Other authors suggest that different mechanisms of the effect may be specific to different respondent groups. The possibilities for generalization of the results of different studies of the nature of emotional Stroop effect are limited by the fact that different researchers use very different sets of stimuli, rely on insufficient sets of independent variable levels, do not analyze individual participant data, and focus on too narrow hypotheses.