The invention relates to a corridor indicator lamp (1). The corridor indicator lamp (1) comprises a base assembly (12) which includes a plurality of compartments (4) and a plurality of separator walls (46). The compartments (4) are open towards a front side (14) of the corridor indicator lamp (1), the separator walls (46) separate at least some of the plurality of compartments (4). In order to improve visibility of the indicator lamp (1) when it is mounted at locations where it may be partly obscured from view, an extension unit (54) is provided according to the invention. The extension unit is configured to be mounted to the base assembly (12) and has a plurality of extension walls (58). When the extension unit (54) is mounted to the base assembly (12), at least some of the plurality of compartments (4) are extended in a direction pointing away from the base assembly (12), thus increasing the height (22) of the corridor indicator lamp (1). An at least partly transparent cover (16) may be further provided, which is adapted to receive the extension unit (54) and may be configured to be attached to the base assembly (12) as a replacement to a flatter cover (16).