A pretty standard US WWII Army HBT utility jacket with black 13 star buttons. The jacket here appears to be a late war third pattern. The 1943 pattern was very similar to the second but with an addition of a gas flap and buttons at the back of the collar and it was made in the darker shade (OD #7). These were mostly issued in 1944 or later.
The HBT uniform was originally intended to be only for work but became the standard dress for all types of mild weather activity, including combat. Gradually replacing the cotton khaki uniform. Additionally these uniforms were always larger than their size indicated they were also used as an outer layer over wool uniforms in very cold weather locations.
I would appreciate any hep identifying the trousers; they appear to be WWII era and have the black 13 star buttons but do not appear to be herring bone twill? Cheers and thanks for looking