The International Congress of Orientalists, initiated in Paris in 1873, was an international conference of Orientalists. It was later renamed as the International Congress of Human Sciences in Asia and North Africa and then as the International Congress of Asian and North African Studies. This material covers the interaction of the Royal Asiatic Society with the Congress in the time period 1889 to 1993.

The 20th International Congress of Orientalists was held in Brussels in September 1938. The material connected to this congress is:

• Letter from Dr G. Ryckmans, Institut Orientaliste de l'Université de Louvain, to the Director of the Journal of the Royal Asiatic Society to inform that the place of the forthcoming conference is likely to be in Brussels. Handwritten with printed letterhead, dated 17 December 1937.
• Letter from Col. Hoysted, Secretary, Royal Asiatic Society, to Dr. G. Ryckmans, Institut Orientaliste de l'Université de Louvain, to thank for his letter and warning about the 20th Congress and to state that he had cancelled the prepared statement for the Journal of the Society. Typed, dated 8 January 1938.
• "Première Circulaire" for the 20th Congress to state that it will be held in Brussels from 5-10 September 1938. Printed in French with handwritten annotations, dated January 1938.
• Letter from Jean Capart, Secretary-General, and L. de la Vallée Poussin, President, Organising Committee, to invite a delegate from the receiving organisation. Printed in French with handwritten annotations, dated 10 February 1938.
• "Deuxième Circulaire" for the 20th Congress giving administrative information and providing a form to subsribe to the "Bulletin D'Inscription". Printed in French, dated April 1938.
• "Troisième Circulaire" for the 20th Congress giving more detailed logistical information. Within the circular is a "Bulletin D'Inscription" form partially completed for Louise Wallace Hackney. Printed in French with handwritten annotations, dated June 1938.
• Letter from Louise Wallace Hackney to Colonel Hoysted to state that she had completed and sent a form previously. She is unsure where she will be staying for the Congress. Handwritten, dated 17 July 1938.
• Letter from Thomas Cook and Son Ltd., to Colonel Hoysted to send copies of an itinerary for arrangements for the 20th Congress. Typed, dated 20 July 1938. The itinerary is with the letter.
• Letter from Col. Hoysted to Thomas Cook and Sons Ltd. to thank for the details of their tour to Brussels for the International Congress. Typed, dated 21 July 1938.
• Letter from Thomas Cook and Son Ltd., to Colonel Hoysted to ask whether a venue and date for the next Congress had been decided at the Brussels conference. Typed, dated 21 September 1938.
• Letter from Col. Hoysted to the Secretary General, XXth International Congress of Orientalists, to ask whether any arrangements of the place and date of the 21st Congress had been made. Typed, dated 4 October 1938.
• Letter from Col. Hoysted to Thomas Cook and Sons Ltd. to state he was unable to give any information concerning the 21st Congress. Typed, dated 20 October 1938.