Abstract Climate change is dramatically affecting small-scale farming productivity in the global south. The phenotypic and pedoclimatic characterization of indigenous crop resources may provide an opportunity to address future challenges threatening food security. This study focuses on a vast Ethiopian ex situ teff collection, comprising 3850 accessions sampled from a range of agroecologies across the country. Eleven phenotypic traits were collected in an experimental field to describe the diversity existing in the collection, unveiling a broad variation for a number of traits of breeding relevance. The sampling information available for 2084 accessions was used to describe the teff growing range in relation to 19 bioclimatic variables and soil features. The geographic distribution of the collection showed that different teff accessions are cultivated in a broad range of environments with diverse bioclimatic features. The combination of phenotypic and pedoclimatic diversity in the collection showed the differential distribution of trait values in relation to different agroecologies. A species distribution model was developed using the bioclimatic characterization of the current teff cropping area. When applied to climate projections, the model showed that the suitability of teff cultivation will diminish by 2070, supporting the need for breeding and conservation efforts tapping the great diversity available in Ethiopian teff.