Estrogens favor glucose homeostasis primarily through the estrogen receptor-α (ERα), but the respective importance of nuclear ERα (NOER) and membrane ERα (MOER) pools to glucose homeostasis are unknown. We studied glucose homeostasis, insulin secretion, and insulin sensitivity in male and female mice expressing either the NOER or the MOER. Male and female MOER mice exhibited fasting and fed hyperglycemia and glucose intolerance. Female MOER mice displayed impaired central insulin signaling associated with hyperinsulinemia and insulin resistance due to unrestrained hepatic gluconeogenesis, without alterations in glucose-stimulated insulin secretion (GSIS). In contrast, male MOER mice did not exhibit detectable insulin resistance, but showed impaired GSIS associated with reduced brain glucose sensing. Female NOER mice exhibited milder hepatic insulin resistance and glucose intolerance. In conclusion, nuclear ERα signaling is predominant in maintaining glucose homeostasis in mice of both sexes. Lack of nuclear ERα alters the central control of insulin sensitivity in females and predominantly impairs the central regulation of insulin secretion in males.