This chapter reviews seedling handedness in some angiosperm families. In dicots the first pair of alternate plumular leaves above the cotyledons show vernation/contortion in which the first leaf that encloses the second is seen either to the left or right in Fabaceae, which was first observed by Bahadur and his associates. In monocots several taxa of Poaceae (Gramineae) show seedling handedness in respect of the folding of the first leaf above the coleoptiles either to the left- or right-hand side. Compton was the first to study seedling handedness in some cereals over 100 years ago, but his work remained unnoticed by the scientific community until Kihara and his associates from Japan revived handedness research and related aspects. In general, the ratio of left- to right-handed seedlings is equal in a sample irrespective of seedling handedness in monocot or dicot plants. The importance of seedling handedness in taxonomy of Poaceae and Fabaceae are discussed as also the yield parameters in relation to handedness wherever possible. Handedness observed in seedling leaves gets extended upward till flag leaves and even to the spikelets in Poaceae. There is conclusive evidence that the direction of folding, in both monocot and dicot seedlings, of leaves may be due to the environmental factor. Seedling handedness in Polygonaceae is also described for the first time.