This paper describes the evolution of capital income taxation in Sweden between 1862 and 2013, including the taxation of corporate profits, dividends, capital gains, interest income, and wealth taxation. To illustrate this evolution, we present annual time-series data regarding the marginal effective tax rates on capital income (METR) for a marginal investment financed with new share issues, retained earnings or debt. The METR is low and stable and does not exceed five percent until World War I, when it begins to drift somewhat upward and vary depending on the source of finance. The outbreak of World War II begins a period during which the magnitude and variation of the METR sharply increase. The METR peaks during the 1970s and 1980s and often exceeds 100 percent. The 1990–1991 tax reform and lower rates of inflation reduce the magnitude and variation of the METR, which varies between 15 and 35 percent at the end of the period examined.