Workplace climate refers to formal and informal organizational characteristics contributing to employee welfare. Workplace climates for lesbian, gay, bisexual, and transgendered (LGBT) employees range from actively supportive to openly hostile. An instrument measuring LGBT workplace climate will enable research on vocational adjustment of LGBT workers and will benefit practitioners doing vocational counseling and consultants working to improve corporate environments. Three rounds of data collection contributed to the construction and validation of the LGBT Climate Inventory (LGBTCI). Use of qualitative data in item construction contributes to content validity. Factor analysis suggests that the LGBTCI measures a single construct. Measures of related constructs (work satisfaction and discrimination) correlate moderately with the LGBTCI, supporting its construct validity. The LGBTCI demonstrates excellent internal and test-retest reliability.