Adolf of Altena, Adolf of Berg or Adolf of Cologne, (c. 1157 – 15 April 1220 in Neuss) was Archbishop of Cologne from 1193 to 1205.
Adolf was born about 1157 as the second son of Count Eberhard of Berg-Altena and his wife Adelheid.
About 1177 he became a canon of Cologne Cathedral. Later, in 1183, he became Dean of the Cathedral, and in the year 1191 Cathedral Provost. He became Archbishop of Cologne in 1193, as Adolf I, or Adolf I von Altena.
In 1194 he was instrumental in arranging the release of King Richard I of England, whom he received with considerable solemnity in Cologne shortly afterwards, at the beginning of February 1194. He was a declared opponent of the plans for a hereditary empire of Emperor Henry VI and at Christmas 1195 refused Henry's wish for the election of his son Frederick Roger. He gave up his opposition in August 1197 for the secondary election of the candidate chosen in the meantime by the other Electors. However, after the death of Henry VI, Adolf declared the election invalid, as the candidate was not baptised and the Emperor had put the Electors under pressure.
In the ensuing dynastic struggle for the throne between the Hohenstaufen and the Welfs, he crowned on 12 July 1198 the Welf Otto of Brunswick in Aachen as King of the Romans (or German king). Shortly afterwards, Pope Innocent III, who had an interest in weakening the Hohenstaufen and in breaking their power (particularly in Italy), confirmed the election of Otto. On 6 January 1205 however Adolf then crowned the Staufer competitor for the crown, Philip of Swabia, as German king. Philip had already been crowned in 1198, although only in Mainz Cathedral, but he had nevertheless been crowned with the genuine Imperial Regalia and especially the Imperial crown.