Grillo-Theater, Municipal theater in central Essen, Germany.

Grillo-Theater is a theatre building in central Essen, originally designed by Heinrich Seeling in neo-baroque style and opened in 1892. Its historicist façade was largely destroyed in World War II and rebuilt in simplified form by Wilhelm Seidensticker and Johannes Dorsch. The auditorium, reduced to 400 seats in a 1990 reconstruction by Werner Ruhnau, faces the Kettwiger Straße.

The city theatre opened on 16 September 1892 with Lessing's Minna von Barnhelm, built in neo-baroque style to a design by Berlin architect Heinrich Seeling after a competition with 34 entrants. Wilhelmine Grillo, widow of industrialist Friedrich Grillo, donated the site and over two-thirds of the 937,997 Mark cost. Badly damaged in World War II, it reopened in 1950 with Wagner's Die Meistersinger von Nürnberg after a rebuild by Wilhelm Seidensticker and Johannes Dorsch.

The theatre is named after industrialist Friedrich Grillo, who pledged 500,000 marks for its construction in 1887 but died before it opened; his widow Wilhelmine funded over two-thirds of the 937,997-mark cost. The opening on 16 September 1892 featured Beethoven's Die Weihe des Hauses and Lessing's Minna von Barnhelm. Since 1988 the Grillo-Theater has served as the main stage of Essen's Schauspiel ensemble.

The main entrance faces Kettwiger Straße, under a dome above the stage house; the 1892 building stood 16 metres high. The auditorium was reduced from 670 to 400 seats in Werner Ruhnau's reconstruction, which reopened in September 1990. Sculptor Herbert Lungwitz made three reliefs for the main entrance area around 1950.

The stage house behind the theatre, built in 1907–1908 for 75,000 marks to replace a provisional scenery store in a former Catholic school, was placed under monument protection in 2006 together with its connecting bridge to the theatre.