Plant heat shock transcription factors (Hsfs) areimportant regulators of heat shock signal transduction pathway. There are 30 members of the Hsf family in maize, only twoof which, ZmHsf06 and ZmHsf12, belong to subclass A1. Our previous work demonstrated that ZmHsf06-overexpressingArabidopsis lines showed improved tolerance to heat anddrought stresses. In this study, we isolated ZmHsf12 fromyoung leaves of maize (Zea mays L.) using homologouscloning methods. The CDS (coding sequence) of ZmHsf12 is1,494 bp and encodes a putative protein consisting of 497amino acids which possesses domains such as DBD (DNAbindingdomain), OD (oligomerization domain), NLS (nuclearlocalization signal), NES (nuclear export signal), and anAHA (activator) motif. The ZmHsf12-GFP fusion protein islocalized to the cell nucleus. ZmHsf12 was expressed inmany maize organs, and its expression was up-regulated byheat shock. Furthermore, we characterized the function ofZmHsf12 in yeast and Arabidopsis. Yeast cells overexpressingZmHsf12 showed enhanced heat tolerance. ZmHsf12-overexpressing Arabidopsis seedlings displayed significantincreases in both basal and acquired thermotolerance. Comparedto WT seedlings, the ZmHsf12-overexpressing lines displayedboth increased chlorophyll contents and higher survivalrates. Also, the expression of AtHsps was increased higher inthe ZmHsf12-overexpressing Arabidopsis lines after heatstress. The results of our study strongly suggested thatZmHsf12 may take part in plant response to heat stress.