The present invention concerns a method for enhancing yield-related traits in plants, particularly increasing seed yield, by modulating expression in a plant of a nucleic acid encoding a Class III Trehalose Phosphate Phosphatase (TPP) polypeptide. The present invention also concerns plants having modulated expression of a nucleic acid encoding a Class III TPP polypeptide, which plants have enhanced yield-related traits relative to control plants. The invention further concerns novel Class III TPP nucleic acid and polypeptide sequences. The invention also provides nucleic acid and polypeptide sequences, and constructs comprising the same, which are useful in the methods of the invention.