On the six-loop scaling dimensions of the (ϕ2) operators in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si9.svg"> <mml:mrow> <mml:mi>d</mml:mi> <mml:mo linebreak="goodbreak">=</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:math>

We consider a class of singlet operators ( ϕ 2 ) n in the three-dimensional O ( N ) model with λ 2 ϕ 6 interaction. Recently [1], the corresponding anomalous dimensions γ 2 n were computed by semiclassical methods and the all-loop result for the leading- n corrections in the small λ limit was found. In this paper, we obtain the six-loop expressions not only for the leading- n contribution but also for the subleading one. While the leading correction confirms the predictions of recent semiclassical calculation, the subleading one is a new result and will serve as a future welcome check for all-loop expressions. As an important by-product of our calculation, we provide a full dependence on n of the four-loop γ 2 n in the O ( N ) case.