Introduction: The suitability of 52 items for measuring Teacher Efficacy was investigated with the aim of developing and validating a Teacher Efficacy Scale (TES) for Nigerian secondary school teachers. Method: The TES was administered on 2400 teachers (mean age = 36.75 years). Data were subjected to factor and reliability analyses. Results: Twenty-eight items were dropped, resulting in the retention of 24 items on the final version. The instrument had a Cronbach's Alpha and Split-half reliability coefficients of 0.88 and 0.90 respectively. Exploratory Factor Analysis revealed that the items on the final version of TES loaded on two factors, which accounted for 46.40% of the total scale variance. They are "efficacy to influence students' learning" (Cronbach's Alpha = 0.86), and "efficacy to enlist parental support in students' learning" (Cronbach's Alpha = 0.72). Conclusion: It was concluded that the 24-item TES in its present form was capable of effectively measuring TE among secondary school teachers. (Contains 9 tables and 2 figures.)