Rudolf Duala Manga Bell (1873 – 8 August 1914) was a Duala king and resistance leader in the German colony of Kamerun (Cameroon). After being educated in both Kamerun and Europe, he succeeded his father Manga Ndumbe Bell on 2nd September 1908.

Bell styled himself after European rulers and at first generally supported the colonial German authorities. He was quite wealthy and educated, although his father left him a substantial debt.

In 1910, the German Reichstag developed a plan to relocate the Duala people living along the river, to be moved inland to allow for wholly European riverside settlements. Manga Bell became the leader of pan-Duala resistance to the policy. He and the other chiefs at first pressured the administration through letters, petitions, and legal arguments, but these were ignored or rebutted. Manga Bell turned to other European governments for aid, and he sent representatives to the leaders of other Cameroonian peoples to suggest the overthrow of the German regime.

Sultan Ibrahim Njoya of the Bamum people reported Bell's actions to the authorities, and the Duala leader was arrested. After a summary trial, Manga Bell was hanged for high treason on the 8th of August 1914. His actions made him a martyr in Cameroonian eyes. Writers such as Mark W. DeLancey, Mark Dike DeLancey, and Helmuth Stoecker view his actions as an early example of Cameroonian nationalism.

Manga Bell was born in 1873 in Douala in an area that would later become part of the German colony of Kamerun. He was the eldest son of Manga Ndumbe Bell, king of the Bell lineage of the Duala people. Manga Bell was raised to appreciate both African and European ways of life. His Westernized uncle David Mandessi Bell had a great impact on him, and as a youth he attended school in both Douala and Germany. During the 1890s he attended the Gymnasium of Ulm, Germany, although no direct record of his time there survived. Manga Bell was made Ein-Jähriger, indicating that he held a certificate for education beyond the primary level but below the Abitur earned for completion of secondary studies. When the prince returned to Kamerun, he was one of the most highly educated men in the colony by Western standards. He made other periodic visits to Europe, such as when he travelled to Berlin, Germany, and Manchester, England, with his father in 1902. In Manchester, he met the mayor at town hall and was mentioned in the October edition of the African Times (where the editor doubted that he and his father were actual royalty). Manga Bell married Emily Engome Dayas, the daughter of an English trader and a Duala woman.

When his father died on 2 September 1908, Manga Bell succeeded as the king of the Duala Bell lineage. He was traditionally installed on 2nd May 1910 by the paramount chief of Bonaberi. Manga Bell inherited an 8,000 mark pension, cocoa and timber interests in the Mungo River valley, property and real estate in Douala, and a lucrative position as head of an appeals court with jurisdiction over the Cameroon littoral. His father and grandfather, Ndumbe Lobe Bell, left him in a strong political position with Bell dominant over the other Duala lineages. However, his father also left him a substantial debt of 7,000 marks. Rudolf Duala Manga Bell was forced to rent buildings to European interests and move his own offices inland to the Douala neighbourhood of Bali. He owned 200 hectares of cocoa plantations in 1913, a large amount by Duala standards; his debt had been reduced to 3,000 marks by 13 July 1912.

Manga Bell's reign was European in character. His relations with the Germans were largely positive, and he was viewed as a good citizen and collaborator. Nevertheless, at times he ran afoul of the colonial administrators. In 1910, for example, the German authorities arrested him and accused him (with no proof) of collusion with a large bank robbery.

Manga Bell's real problems with the regime began later in 1910. The Germans outlined a plan to relocate the Duala people inland from the Wouri River to allow European-only settlement of the area. The expropriations affected all of the Duala lineages except Bonaberi, so Duala public opinion was strongly against it, and for the first time in their history, the Duala clans presented a united front. Manga Bell's position as leader of the dominant Bell clan, coupled with his character, education, and finances, made him a natural leader for this opposition. Manga Bell and other Duala rulers sent a letter to the Reichstag in November 1911 to protest the land seizures. The Germans were surprised at Manga Bell's involvement, but they ignored the complaint. The chiefs sent another letter in March 1912. Still, the Germans moved forward with their plan on 15 January 1913. The chiefs warned in writing on 20 February 1913 that this violation "may well prompt the natives to consider whether it might be wiser under the circumstances to revoke the [German-Duala Treaty of 1884 and enter into a treaty with another power." Manga Bell argued that the expropriation plan ignored the treaty's promise "that the land cultivated by us now and the places the towns are built on shall be the property of the present owners and their successors" and contradicted statements by Governor Theodor Seitz that he would leave Bell lands alone as he constructed a railroad in the colony. The Germans countered that the German-Duala treaty gave them the authority to manage Duala lands as they saw fit. That August, they removed Manga Bell from office and from the civil service and stripped him of his annual pension of 3,000 marks. In his place, they propped up his brother, Henri Lobe Bell.