Selenium (Se) affects gonadal function, and the form of Se provided to cows affects tissue-specific gene expression. The objective of this study was therefore to determine whether the form of Se consumed by cows would affect follicular growth and the production of ovarian steroids. Pasture-fed Angus crossbred cows were randomly assigned to have ad libitum access to free-choice vitamin-mineral mixes containing Se (35 ppm) in either (TRT) inorganic (ISe, n = 41), organic (OSe, n = 42), or a 50/50 mix of ISe and OSe (MIX, n = 44) forms for 175 d. A subset of these cows (n = 9–11 per TRT) with a detectable corpus luteum were maintained on TRT and administered 25 mg PGF_2α to induce luteal regression, then assigned for further sampling on estrus (Day 0). Between Day 4 and 8, follicular diameter was determined by ultrasonography. On Day 6, cows were treated with 20 mg then 15 mg PGF_2α, 8 to 12 h apart, to induce luteal regression and differentiation of the first-wave dominant follicle into a preovulatory follicle. On Day 8, 36 h after PGF_2α, the contents of the preovulatory follicle were aspirated by ultrasound-guided follicular puncture. Progesterone and estradiol were determined in plasma collected on Day 6 and 8, and in follicular fluid collected on Day 8. TRT effects were assessed by ANOVA and Fisher’s LSD. TRT affected (P < 0.02, OSe > MIX) total blood Se (OSe: 156 ± 5, ISe: 146 ± 4, MIX: 140 ± 6 µg/mL). TRT affected (P < 0.04, MIX > ISe) systemic progesterone on Day 6 (MIX: 5.1 ± 0.6, OSe: 4.6 ± 0.5, ISe: 3.4 ± 0.2 ng/mL) but not Day 8. TRT did not affect systemic estradiol on Day 6 or 8. TRT tended (P = 0.07, OSe > MIX, ISe) to affect follicular fluid progesterone (OSe: 58.9 ± 11.5, MIX: 44.4 ± 3.8, ISe: 30.5 ± 8.1 ng/mL) but not estradiol. TRT did not affect diameter of the dominant follicle on Days 4 to 6, and tended (P = 0.08, ISe > OSe, MIX) to affect the diameter of the preovulatory follicle on Day 8 (ISe: 12.6 ± 0.6, OSe: 11.4 ± 0.3, MIX: 11.3 ± 0.4 mm). Our results indicate that form of Se fed to cows affects progesterone but not estradiol synthesis, and tends to affect follicular diameter, in a manner independent of total blood Se concentrations.