The last two decades revealed a plethora of scientific examinations on the Dark Triad (narcissism, psychopathy, Machiavellianism) and Dark Tetrad traits (Dark Triad + sadism) in a variety of contexts. Short scales for the assessment of these traits have been very influential and widely used. Building upon previous research, the 28-item Short Dark Tetrad (SD4) was introduced as a measure for the assessment of the Dark Tetrad traits. A recent study found that the SD4 is invariant across genders, but little is known concerning invariance across cultures. Therefore, we tested measurement invariance (MI) between German and US participants. Additionally, we replicated extant findings on MI across genders. The analyses suggested configural MI across cultures, metric MI between genders in a US sample, and scalar MI across genders in a German sample. To address that the SD4 revealed only modest fit in the samples, we further computed Exploratory Structural Equation Models. Those were mostly consistent with the original model structure and indicated that adding marginal cross-loadings among the factors accounts for enhanced model fit. Possible explanations for the findings related to MI were discussed.