The present invention provides an aircraft structure comprising a first sub-structure, having a first box cross-section, a second sub-structure, having a second box cross-section, and a joint joining a first end region of the first sub-structure to second end region of the second sub-structure, wherein the joint comprises an overlap region where the end regions of the first and the second sub-structures overlap such that the first sub-structure is inside the second sub-structure. The present invention also provides an aircraft comprising such an aircraft structure and a method of manufacturing an aircraft structure.