A reinforced geocell is made of flexible polymeric strips arranged in rows and interconnected in a staggered order lengthwise to form a three-dimensional cell structure when stretched in the direction normal to surfaces of the strips. The strips are provided with drainage apertures and are reinforced in a longitudinal direction with reinforcing threads having at least two fibrous elements twisted along full lengths thereof. A method for producing a geocell includes extruding a polymeric material for producing a sheet material, laying out twisted reinforcing threads onto the sheet material, calendaring the sheet material when heated to 120 to 200° C. to press reinforcing threads into the sheet material, cutting a reinforced sheet material into sheets, perforating the sheets for producing drainage apertures, cutting the sheets into strips, and interconnecting the strips in a staggered order to form a three-dimensional cell structure.