Slender Godetia is a slender, erect, simple or branched annual with stems from 15-60 cm high. The herbage varies from glabrous below to covered with white, appressed hairs above. The leaves are linear-lanceolate to broadly lanceolate with entire margins and taper gradually to a slender petiole. They measure from 3-6 cm long.
The flowers are found at the top of the stem, arising from the leaf axils. The tip of the inflorescence and the unopened buds are recurved to the side or downwards, only becoming erect as the flowers open. The sepals are joined and turned to one side beneath the flower. The hypanthium is 1-3 mm long. The 4 pink to lavender petals lack spots and measure from 8-20 mm long. The cream colored stigma lobes are 1-1.5 mm long while the style is shorter than the stamens. At flowering, the ovary is longitudinally 4-grooved. The cylindrical capsules are straight, 3-5 cm long, and widest at the middle, tapering gradually to each end.
Slender Godetia is similar to herald-of-summer, Clarkia amoena as well as Lassen Clarkia Clarkia lassensis. The petals of the latter are larger and typically spotted, and the tip of the inflorescence is upturned before flowering. The latter species has an ovary that is 8-grooved.
Slender Godetia is found in open, grassy meadows and prairies.
Slender Godetia is found from Walla Walla County in Washington west to Klickitat County (WA) and Wasco County (OR) and the White Salmon River in the Columbia River Gorge and then west of the Cascade Mts, it is found south to central California.