In response to conflicting reward (Behavioral Approach System [BAS]) and/or punishment cues (Fight-Flight-Freeze System [FFFS]) the Behavioral Inhibition System (BIS) inhibits behavior, leading to increased attention to threat, high anxiety, and behavioral ambivalence. The role of BIS in alcohol misuse is complex, as anxiety promotes self-medication drinking, while attention to threat (e.g., negative outcomes of heavy drinking) may reduce risk. Theory suggests that a concurrent strong BAS may bias BIS-conflict in favor of alcohol approach, while a concurrent strong FFFS may increase the likelihood of alcohol avoidance. However, few studies measure BIS as a conflict system, and no studies incorporate such a measure into examinations of alcohol misuse. Our study goals were to (i) test the Motivational Flanker Task (MFT) as a new laboratory measure of the BIS, BAS, and FFFS; and (ii) use the MFT, in conjunction with self-report measures, to test BAS and FFFS as moderators of the BIS-alcohol misuse relation. We hypothesized that an elevated BIS would predict heavy drinking and alcohol-related problems, but only when BAS was high. Further, we expected an elevated BIS to be associated with reduced alcohol misuse, but only when FFFS was high.