Metacognition's roles in self-regulation of cognitive tactics and strategies is explored in relation to five sites where individual difference factors are likely to be observed and affect performance: domain knowledge, knowledge of tactics and strategies, performance of tactics and strategies, regulation of tactics and strategies, and global dispositions. Though the current literature is sparse, tentative hypotheses about kinds of individual differences and their impact are proposed. Directions for future research are noted concerning the need for more sophisticated metacognitively-based models of SRL as a complex collection of individual differences, and some suggestions are made about methodologies for investigating complex, metacognitively regulated approaches to learning.