Spirou (French: Le Journal de Spirou) is a weekly Belgian comics magazine published by the Dupuis company since April 21, 1938. It is an anthology magazine with new features appearing regularly, containing a mix of short humor strips and serialized features, of which the most popular series would be collected as albums by Dupuis afterwards.

With the success of the weekly magazine Le Journal de Mickey in France, and the popularity of the weekly Adventures of Tintin in Le Petit Vingtième, many new comic magazines or youth magazines with comics appeared in France and Belgium in the second half of the 1930s. In 1936, the experienced publisher Jean Dupuis put his sons Paul and the 19-year-old Charles in charge of a new magazine aimed at the juvenile market.

First appearing 21 April 1938, it was a large format magazine, available only in French and only in Wallonia. It was a sixteen-page weekly comics magazine composed of a mixture of short stories and gags, serial comics and short articles. It introduced two new comics, the eponymous Spirou drawn by the young Frenchman Rob-Vel, and Les Aventures de Tif (later to become Tif et Tondu) written and drawn by Fernand Dineur, and printed American comics such as Superman, Red Ryder and Brick Bradford. On 27 October 1938 the Flemish edition named Robbedoes appeared as well.

Spirou and Robbedoes soon became very popular and the magazine doubled its pages from 8 to 16. After the invasion of the Germans, the magazine gradually had to stop publishing American comics. They were at first continued by local artists and later replaced with new series. When Rob-Vel no longer had the possibility to send his pages from France to Belgium on a regular basis either, his series was continued by Joseph Gillain, a young artist who had previously worked for Petits Belges and used the pen name Jijé. Together with Dineur and Sirius (pen name of Max Mayeu), they filled the magazine with a number of new series and increased the popularity of it even further.

Near the end of the war, due to paper shortages, publication had to be stopped anyway, with only a few irregular almanacs to keep the bond with the readers intact and to provide work for the personnel to prevent them being deported to Germany.

The period 1945–1960 has been described by critics as the golden age of Spirou magazine and of Belgian comics in general, partly incited by the 1946 appearance of the successful competitor Tintin magazine. Spirou resumed publication only weeks after Belgium was liberated, but now on a much smaller format. Jijé was the main author, providing pages from multiple series each week. Some American comics reappeared as well. Jijé started out a studio, where he schooled three talented apprentices, Will, André Franquin and Morris; known as the "Bande à quatre", "Gang of four", they began laying the foundation for the Marcinelle school that marked the magazine for decades.

In 1946 and 1947, the team was joined by some of the main contributors to Spirou for the next decades, including Victor Hubinon, Jean-Michel Charlier and Eddy Paape. After a few years, these artists started their now classic series like Buck Danny by Hubinon and Charlier and Lucky Luke by Morris, while Franquin took over Spirou from Jijé. Gradually, the American comics and reprints were replaced by new, European productions, and by the 50s, nearly all the content was made especially for the magazine. Charles Dupuis remained editor-in-chief of the magazine until 1955 when he appointed Yvan Delporte to that position, so he could himself focus on his increasing interest in the publication of the magazine's series' albums.

The golden ages culminated in the 1950s with the introduction of more authors and series like Peyo (Johan and Peewit in 1952, The Smurfs in 1958), René Follet, Marcel Remacle, Jean Roba (with Boule et Bill), Maurice Tillieux (with Gil Jourdan) and Mitacq. In 1954, Jijé created the realistic western comic Jerry Spring, and in 1957 Franquin introduced the anti-hero Gaston Lagaffe. The authors of the magazine, many of them pupils of Jijé, were grouped stylistically in the Marcinelle school, the counterpart of ligne claire exhibited by the artists grouped around Hergé in Tintin magazine (the main competitor for Spirou).