A carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B) for holding one or more articles, the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B) comprising: a plurality of panels extending at least partially around an interior of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B), the plurality of panels comprising a front panel (21, 321), a back panel (31, 331), a first side panel, and a second side panel; a plurality of end flaps foldably connected to respective panels of the plurality of panels and forming a closed top portion (9, 9A, 9B) of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B), the plurality of end flaps comprising a first top end flap foldably connected to the first side panel and a second top end flap foldably connected to the second side panel, the closed top portion (9, 9A, 9B) of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B) is reconfigurable between a first configuration having a substantially flat profile and a second configuration forming a handle of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B); and locking features (133, 135) for engaging at least one other carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B), characterised in that the locking features (133, 135) comprise a first locking tab foldably connected to the first top end flap, a second locking tab foldably connected to the second top end flap, a first locking flap foldably connected to the first side panel, and a second locking flap foldably connected to the second side panel, wherein each of the first locking tab and the second locking tab have respective flange portions (117, 119) that extend laterally away from respective fold lines (113, 115) such that a respective pair of engagement notches (121, 123) is formed between the respective locking tabs (109, 111) and the remainder of the respective top end flaps (73, 77), and the locking tabs (109, 111) are configured to be insertable into respective openings between the respective locking flaps (39, 45) and the respective side panels (23, 25) of another carton to secure multiple cartons to each other in a system. a plurality of panels extending at least partially around an interior of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B), the plurality of panels comprising a front panel (21, 321), a back panel (31, 331), a first side panel, and a second side panel; a plurality of end flaps foldably connected to respective panels of the plurality of panels and forming a closed top portion (9, 9A, 9B) of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B), the plurality of end flaps comprising a first top end flap foldably connected to the first side panel and a second top end flap foldably connected to the second side panel, the closed top portion (9, 9A, 9B) of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B) is reconfigurable between a first configuration having a substantially flat profile and a second configuration forming a handle of the carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B); and locking features (133, 135) for engaging at least one other carton (5, 5A, 5B, 205A, 205B, 305, 305A, 305B, 405, 405A, 405B), characterised in that the locking features (133, 135) comprise a first locking tab foldably connected to the first top end flap, a second locking tab foldably connected to the second top end flap, a first locking flap foldably connected to the first side panel, and a second locking flap foldably connected to the second side panel, wherein each of the first locking tab and the second locking tab have respective flange portions (117, 119) that extend laterally away from respective fold lines (113, 115) such that a respective pair of engagement notches (121, 123) is formed between the respective locking tabs (109, 111) and the remainder of the respective top end flaps (73, 77), and the locking tabs (109, 111) are configured to be insertable into respective openings between the respective locking flaps (39, 45) and the respective side panels (23, 25) of another carton to secure multiple cartons to each other in a system.