Persons with amnestic Mild Cognitive Impairment (aMCI) are at risk for experiencing changes in their daily functioning due to their memory impairment. The Memory Support System (MSS), a compensatory calendaring system, was developed to support functional independence in persons with aMCI (pwaMCI). This cross-sectional study examined procedural learning, declarative learning, and working memory as predictors of MSS learning efficiency in pwaMCI. Sixty pwaMCI participated in MSS training. The Serial Reaction Time Test and Mirror Tracing Test were used to assess procedural learning. The Rey Auditory Verbal Learning Test and CogState One Card Learning were used to assess declarative learning and the CogState One Back task was used to assess working memory. Multiple regression analyses were conducted to assess if procedural learning, declarative learning, and working memory predicted MSS learning efficiency. This study showed that declarative learning predicted MSS learning efficiency in pwaMCI, with less consistent results for procedural learning and non-significant results for working memory. Findings suggest that success in teaching compensatory tools is greater when training is offered in early aMCI before declarative learning skill is fully lost. Future studies should assess additional strategies to facilitate MSS learning in advanced aMCI.