Geoxyles and their congeneric tree species are a very common feature in the Zambezian Floristic Region, however, little is known about differing expression of plant functional traits between the two life forms and thus their evolutionary adaptations to prevailing habitat conditions. Therefore, we measured selected plant functional traits and compared them between the geoxyle and tree growth forms. We selected six species pairs that are common in the study area, i.e. Brachystegia russelliae vs. Brachystegia longifolia (Fabaceae–Detarioideae); Cryptosepalum exfoliatum subsp. suffruticans vs. Cryptosepalum exfoliatum subsp. pseudotaxus (Fabaceae–Detarioideae); Combretum platypetalum vs. Combretum zeyheri (Combretaceae); Parinari capensis vs. Parinari curatellifolia (Chrysobalanaceae); Syzygium guineense subsp. macrocarpum (suffrutex form vs. tree form) (Myrtaceae); Uapaca nitida var. suffrutescens vs. Uapaca nitida var. nitida (Phyllanthaceae). For analysis we selected traits reflecting adaptations to environmental conditions such as specific leaf area (SLA), leaf thickness (LT), wood density (WD), leaf nitrogen (LN), leaf carbon (LC), leaf phosphorus (LP), leaf calcium (LCa), leaf magnesium (LMg), leaf potassium concentrations (LP) and leaf dry matter content (LDMC). Additionally, we measured leaf water potential (WP) during dry and wet seasons. The results did not show a general pattern of inter-life-form trait variation among trees and geoxyles. There were significant differences in LA, WD, LN, LC, LMg and LK between geoxyles and trees, but mostly among species pairs. This indicates that the growth form transition is largely decoupled from leaf economics. Thus, the detected differences in plant functional traits among the species pairs are mostly taxon related responses to specific environmental stresses and habitat conditions.