A study on the flowering plant diversity of Thevarmala sacred grove in the Western Ghats of Kerala region was carried out during the period 2015-2016. During the study a total of 152 species of flowering plants belong to 136 genera under 50 families were documented. Plants in all life forms, viz. herbs (56 species), shrubs (64 species) and trees (32 species) are well represented in the grove. Fabaceae is the dominant family with 15 species in 12 genera followed by Euphorbiaceae and Rubiaceae. As many as 17 families are represented by single species in each. Out of the 152 species 18 are rare endemics especially confined to the southern Western Ghats. About 62 % of the documented plants are having economic importance as medicine (76 species), food (8 species), timber (6 species), and fodder (3 species) or as source of commercially useful fibres and resins. 19 species documented in the present study are new record to the Kottayam district of Kerala state. The present conservation status of this sacred grove and future threats are also discussed in this paper.