The main purpose of this study was to examine the influence of improvement strategies on teachers’ perceived teaching effectiveness in Calabar Metropolis of Cross River State, Nigeria. The research design that was adopted in the conduct of this study is the Ex-Post Facto research design. Ex-post Facto research design is a design where the researcher does not have direct control of the independent variables, because their manifestation has already occurred. The variables involved in the study cannot be manipulated. The population of this study comprised all 6 principals, 72 vice principals and 1290 secondary school teachers in 21 public secondary schools in Calabar Metropolis (State Secondary Education Board, Cross River State, 2021). Calabar Metropolis consist of two Local Government Areas; namely, Calabar South and Calabar Municipality respectively). There are 8 public secondary schools in Calabar South and 16 public secondary schools in Calabar Municipality. Three research questions were poised and three statement of hypotheses were formulated to guide the study. A sample of 309 respondents was used in the study using Taro Yamane’s formula. The instruments that were used for data collection were a questionnaire titled Improvement Strategies; Principals’ Role Scale (ISPRS) and Teachers’ Teaching Effectiveness Questionnaire (TTEQ) designed by the researchers. The instrument that was used for data collection is a questionnaire titled Improvement Strategies and Principals’ Role Scale (ISPRS). The instrument comprised two sections A and B. Section A of the instrument consists of demographic sub-variables meant to obtain personal information about the subjects used in this study. Section B comprised 15-structured items questionnaire covering the sub-variables, in a four-point modified Likert Scale items. The internal consistency of the research instrument (ISQ) was tested using the Cronbach Alpha reliability estimate method. The statistical tool used for analysis is one-way analysis of variance (ANOVA) and the hypotheses were tested at 0.05 level of significance. The findings revealed that there was significant influence of in-service training, motivation and teachers’ involvement in decision-making on teaching effectiveness in public secondary schools in the study area. Based on the findings, it was recommended among others that teachers should be exposed to regular in-service training to help them acquire the requisite skills that will make them productive in their service delivery.