Complete diallel crosses were performed in three Norway spruce stands and in one seed orchard. Results are presented for seed yield and 1000 seed weights. Filled seed percentages were higher for open‐pollinated families than for outcrossed full‐sib families and were lowest for selfed families. A large variation was found between the maternal parent trees for this character and a smaller variation between the paternal parents. No distinction could be made between genetic and environmental variation in filled seed percentages. Two out of 34 parents produced no viable seeds after selfing. Seeds from controlled crosses were heavier than seeds from open pollination. The maternal parent accounted for more than 75% of the total variation in 1000 seed weight. In addition, a small, but statistically significant effect of the male parent was found.