Abstract: The present invention relates to a surfactant composition for use in glyphosate-containing herbicide formulations, comprising from 5 to 50% by weight of one or more amphoteric surfactants, diluted in solvents derived from the process of synthesis thereof, wherein the surfactants have general formula (I) R1—(XR2)m—N+(R3)(R4)—CH2—CH(R5)—COO???(I) wherein R1 is hydrogen or C1-18 hydrocarbyl; each X is independently an ether, thioether, sulfoxide, ester, thioester or amide bond; each R2 is independently a C3-6 chain; m is a number from 0 to 8 such that the number of carbon atoms in R1—(XR2)m is from 8 to 24; R3 and R4 are independently hydrogen or C1-4 chains; R5 is hydrogen or methyl. The surfactant composition is used to increase the agronomic efficacy of herbicide formulations containing a high concentration of glyphosate salts. The present invention further describes herbicide formulations comprising such surfactant composition as well as the use thereof.