A review is undertaken of recent palaeoecological research bearing on a number of the most important Jurassic environmental factors. Temperature is the most significant variable related to global climate, and terrestrial plants provide the best data. Use of the biome method of phytogeography for the Eurasian region leads to some modification of earlier views, but still supports polar regions being much warmer than today, while growth ring studies indicate broad equatorial and temperate climatic belts and a monsoonal climate. Stomatal density studies on leaf cuticles are consistent with there having been a much higher level of atmospheric CO 2 . The degree of oxygenation of the sea bed has been the subject of a number of intensive studies, most notably for the inferred oxygen-deficient environments of the German Posidonienschiefer, the Swiss Opalinus Clay and the English Kimmeridge Clay, and a large amount learned about how to distinguish varying oxygen levels. Important studies of salinity-controlled environments include those of the Bathonian of Scotland, the Kimmeridgian of Portugal and the Bajocian-Callovian of Tunisia, and the use of carbon isotopes as a tool in relation to palaeoecology is discussed. Determination of depth of sea is important for basin analysis but remains a difficult challenge. Significant advances can however be made using a variety of criteria. Among other factors, varying substrates and incidence of light are also amenable to palaeoecological analysis.