Novel polyphenylene ether-polyamide compositions having improved compatibility, elongation and impact properties as well as improved processability are prepared comprising one or more polyphenylene ethers, one or more polyamides and a property improving silane derivative compound having in the molecule both (a) at least one silicon bonded to a carbon through an oxygen link and (b) at least one ethylenic carbon-carbon double bond or carbon-carbon triple bond and/or functional group selected from the group consisting of an amine group or a mercapto group, with the proviso that the functional group is not directly bonded to a silicon atom. These compositions may further comprise a polymeric impact modifier therefore and/or an inorganic reinforcing additive and/or other polymers including alkenyl aromatic polymers.