This paper reviews empirical capital structure research, concentrating on papers published since 2005. We begin by documenting three dimensions of capital structure variation: cross-firm, cross-industry, and within-firm through time. We summarize how well the traditional tradeoff and pecking order approaches explain these sources of variation and highlight their empirical shortcomings. We review recent research that attempts to address these shortcomings, much of which follows the following broad themes: i) Important variables have been mis-measured in empirical tests, ii) The impact of leverage on non-financial stakeholders is important, iii)The supply side of capital affects corporate capital structure, iv) Richer features of financial contracts have been under-researched, v) Value effects due to capital structure appear to be modest over wide ranges of leverage, vi)Estimates of leverage adjustment speeds are biased, vii) Capital structure dynamics have not been adequately † We thank