Abstract. This paper takes up the systematic study of the Gottlieb groups G n+k (S n ) of spheres for k ≤ 13 by means of the classical homotopy theory methods. The groups G n+k (S n ) for k ≤ 7 and k = 10, 12, 13 are fully determined. Partial results on G n+k (S n ) for k = 8, 9, 11 are presented as well. We also show that [ι n , η 2 n σ n+2 ] = 0 if n = 2 i − 7 for i ≥ 4.