Biosensors are promising biotools, alternative or complementary to conventional analysis techniques, for fast, simple, cheap and reliable screening. This article reviews the biosensors that use plant components as biorecognition elements. In the first section, plant tissue-based biosensors are summarised and classified according to the enzyme used. Afterwards, photosynthesis-based biosensors, including the types of photosynthetic materials and immobilisation methods, are described.