The U.S. Marine Corps Training and Education Command is developing a requirement for a set of measures to assess cognitive abilities in support of small unit decision-making challenges. Prior assessment efforts in this area of research have failed to address several key issues, including the multidimensionality of decision making and the ability to predict decision performance across a range of operational settings. This paper reports on the development of a Small Unit Decision Making Assessment Battery that treats decision performance as a multidimensional construct supported by competencies, such as problem solving and attentional control, and cognitive and relational skills, such as perspective taking and resilience. Candidate battery instruments were selected or developed based on their face validity and existing psychometric properties as measures of 15 constructs hypothesized to enable small unit decision making. The instruments were subjected to comprehensive testing with a large population from The Basic School to assess their psychometric properties and to finalize each instrument. Analyses were performed at item, battery, and relationship levels to identify the most meaningful items and improve internal consistency reliability, examine the factor structure of each instrument, and identify the constructs most predictive of decision-making proficiency. Results indicate the predictive ability of the battery and the ability of the battery to distinguish levels of performance by correctly, significantly classifying participants into different performance levels. This research furthers the community's understanding of decision making as a multidimensional construct. Plans for future research and application are discussed.