The invention relates to a surfactant system for use in a herbicidal formulation or for use as an adjuvant to a herbicidal formulation, particularly a glyphosate herbicidal formulation. The surfactant system comprises at least one surfactant selected from the group comprising alkylpolyglycosides as the principal or main surfactant, and at least one surfactant selected from the group comprising alkylbetaines and alkyl(amidoalkyl)betaines as the secondary or minor surfactant. The invention further relates to a herbicidal formulation, particularly a highly concentrated aqueous herbicidal formulation comprising one or more water soluble salts of N-phosphonomethylglycine and the surfactant system, wherein the total content of the surfactant system in the herbicidal formulation is less than 90 g/L, expressed in active content of surfactants. The invention further relates to a method of controlling unwanted vegetation by application of the herbicidal formulation to the vegetation.
