Glioblastoma growth is driven by receptor tyrosine kinase (RTK)-mediated signals. One of the RTK systems recently coming into focus are the fibroblast growth factor (FGF) high-affinity receptors (FGFR1-FGFR4) due to mutation, overexpression or translocation in several cancer types. FGF/FGFR represents a complex signal network with essential functions in embryonic development, tissue homeostasis and wound healing but also for malignant transformation and growth as well as tumor neoangiogenesis and therapy failure. Several studies have suggested a role of FGFRs in human glioblastoma whereby the information on FGFR4 is sparse. Here we investigated whether FGFR4 as compared to FGFR1 blockade impacts on glioblastoma growth in vitro and in vivo. Both in human glioblastoma cell lines (N = 8) and primary cell cultures from clinical samples (N = 26) we found a widespread expression of several FGFs (e.g. FGF1, FGF2, and FGF5) but also a significant overexpression of FGFR1 and FGFR4 in distinct subgroups as compared to non-malignant brain primo cell cultures. Regarding FGFR1 mRNA, all glioma cell models investigated expressed in addition to the FGFR1-IIIb also the mesenchymal and more oncogenic FGFR1-IIIc splice variant. Application of the FGFR inhibitors (nintedanib, ponatinib) as well as expression of dominant-negative (dn) versions of FGFR1 and FGFR4 significantly reduced in vitro cell growth and clonogenicity in the tested glioma cell models whereby dnFGFR1 tended to be more efficient than dnFGFR4. Accordingly, both dominant-negative FGFRs induced significant apoptosis whereby the effects of dnFGFR1 were again significantly stronger. Surprisingly, the inhibitory effects on anchorage-independent growth in soft agar were opposite with significant mitigation by dnFGFR1 but almost complete blockade by dnFGFR4 in the majority of the glioblastoma models analysed. Additionally, neurosphere formation, indicative for the presence of glioma stem cells, was profoundly reduced by both dnFGFRs. Interestingly, FGFR4 belonged to those genes significantly overexpressed in the cancer stem cell compartment (N = 16; mRNA expression arrays of neurosphere versus adherent cell culture). Accordingly, growth of two out of three human glioblastoma xenografts analysed in SCID mice was completely inhibited by dnFGFR4 while only retarded by dnFGFR1. Summarizing our data substantiates a significant contribution of FGF/FGFR-mediated signals to different aspects of glioblastoma aggressiveness and suggests a particular role of FGFR4 in stemness and three-dimensional in vivo growth.