Easily mistaken for : Greater Butterfly-Orchid (Platanthera chlorantha) but that has the two pollinia further apart and splayed out sideways to each other rather than the strictly parallel pollinia of Lesser Butterfly Orchid, this last property being the main differentiating feature between the two.

Hybridizes with : Greater Butterfly-Orchid (Platanthera chlorantha) to produce Platanthera × hybrida.

Un-like Greater Butterfly-Orchid it will also grow in very acidic soils. It is found in grasslands, woods (especially of Beech in Southern England), up to 1200 feet in height on damp hill pastures, moorland, wet heaths, or tussocky marshy ground and near stream flushes which produce less acidic parts of bogs. Much more infrequently found on damp pastures on hills or in chalk grassland and deciduous woods. The spur at the rear of the flower is a long 13-23mm, but usually shorter than that of the 19-35mm of Greater Butterfly-Orchid.

The flower spike has 5-25 flowers (against the 10-40 of those of Greater Butterfly-Orchid. It is usually white-flowered, but if it is growing in a bog then the flowers will be greener.

The flowers smell more strongly (of vanilla) than do those of Greater Butterfly-Orchid.