Commissure features and attachments for prosthetic heart valves are disclosed. As one example, a prosthetic heart valve can include an annular frame comprising a plurality of commissure features, each commissure feature comprising a first sidewall strut, a second sidewall strut, and a central strut situated between the first and second sidewall struts. A plurality of leaflets is arranged within an interior of the frame and secured to one another at adjacent ends to form commissures, each commissure being secured to a respective commissure feature and comprising a first commissure tab of a first leaflet and a second commissure tab of a second leaflet adjacent the first leaflet. The first commissure tab and the second commissure tab each extend inside of the central strut, wrap around a respective sidewall strut, and extend into the interior of the frame.