A capsule for an electronic cigarette has a first end for engaging with an electronic cigarette device and a second end configured as a mouthpiece portion having a vapor outlet, the capsule further including a liquid store configured to contain a liquid to be vaporized, a vaporizing unit including a heater and a fluid transfer element, the vaporizing unit being arranged within a vaporizing chamber, a main vapor channel extending from the vaporizing chamber to the vapor outlet in the mouthpiece, and a housing enclosing the liquid store and the vaporizing unit, wherein the housing includes inner and outer housings that are assembled together, wherein the liquid store is located in a void in-between the inner and outer housings, wherein a seal is provided between the inner and outer housings, and wherein the seal has a cross-sectional shape having a cross-sectional height that is larger than a cross-sectional width.