Proximal sensors have been increasingly used for a variety of purposes worldwide, with great interest on portable X-ray fluorescence (pXRF) spectrometry applications in Soil Science. pXRF provides rapid, inexpensive, non-destructive, and environmentally-friendly elemental analysis in soils, rocks, sediments, plant tissues, water, and other matrices. While temperate regions concentrate the largest number of studies involving pXRF for soil characterization, tropical regions have recently demonstrated increasing interests in—and acceptance of—pXRF applications for soil-related studies due to the wide range of purposes in which this equipment can be utilized. However, the lack of a standard methodology for tropical soil analysis via pXRF coupled with the recognized variation of results according to the procedures used during analyses underlie the need for routine protocols for improving pXRF analyses in tropical environments. Besides establishing such a standard methodology, this review elucidates the main differences between soils from tropical and temperate regions that are key in pXRF research, presents state-of-the-art achievements in pXRF analysis, and envisions applications of pXRF in tropical soils.