The purpose of this study was to develop a measurement instrument to determine pre-service teachers' perceptions of competency in biology teaching. A total of 835 pre-service teachers participated in this study. The data set obtained at the first stage was analyzed using exploratory factor analysis and the data set obtained at the second stage was analyzed using first-order confirmatory factor analysis and then second-order confirmatory factor analysis. After those analyses, the convergent and discriminant validities of the scale with the determined factorial structures [chi 2 (29, N=608) = 101 p<.000, X2/df = 3.48, RMSEA=0.062, GFI=0.97, CFI=0.99, NNFI=0.98, NFI=0.98] were evaluated and Cronbach's alpha, stratified alpha, and McDonald's omega coefficients were estimated for internal consistency. Thus, a scale consisting of four sub-scales with 67 items in total was developed. The total score for the scale can be calculated by adding the scores of the sub-scales.