A　finite　element　thermal　analysis　was　conducted　in　this　study　with　the　aim　of　evaluating　the　influence　of　the　geometrical　parameters　of　steel　sections　on　their　thermal　response　under　solar　radiation.　Four　W12　and　W24　standard　steel　beams　were　investigated　under　the　solar　irradiation　conditions　of　a　sunny　summer　day.　The　finite　element　analysis　was　carried　out　using　COMSOL　Multiphysics　considering　the　Sun＇s　movement　from　sunrise　to　sunset,　reflected　radiation　from　the　ground,　surface　convection　of　air　and　long　wave　radiation　as　the　main　boundary　thermal　loads.　The　temperature-time　variation　at　different　locations　in　the　sections,　vertical　temperature　distributions,　temperature　gradient　distributions　and　thermal　stress　distributions　were　investigated.　The　results　showed　that　the　daily　maximum　temperatures,　temperature　variation,　temperature　and　temperature　gradient　distributions　and　thermal　stresses　are　influenced　by　the　geometry　of　the　steel　section.　The　flange　width　and　flange　thickness　were　found　to　be　the　controlling　parameters　during　the　noon　hours,　while　these　parameters　in　addition　to　web　depth　control　the　shading　effect　during　the　afternoon.　On　the　other　hand,　web　thickness　affects　the　temperature　of　webs　at　sunrise　and　sunset　times.　Geometrical　ratios　like　W-f/H,　W-f/t(f)(2)　and　2W(f)/Ht(f)　were　the　most　influential　parameters　on　temperatures,　temperature　gradients　and　thermal　stresses　of　steel　beams　subjected　to　solar　radiation.　The　investigated　section　with　the　maximum　W-f/t(f)(2)　value　of　0.96　(W12　x　58)　recorded　the　highest　top-surface　noon　temperature,　while　section　W24　x　84　with　the　lowest　W-f/t(f)(2)　value　of　0.60　exhibited　the　lowest　temperature.