The study explored primary school science teachers’ perception of authentic assessment in the Standards-based Curriculum in the Effutu Municipality. The study was modelled on an explanatory sequential mixed methods design. A simple random sampling technique was used to select a sample size of 180 teachers for the quantitative phase out of which four teachers were purposively sampled for the qualitative phase of the study. A structured questionnaire was used to gather the quantitative data on the respondents. Quantitative data was analysed using descriptive statistics (means, standard deviations, frequencies, and percentages) and inferential statistics (One-way ANOVA) was used to analyse the hypotheses. In the qualitative phase, a semi-structured interview guide was used to collect data, and the data from the interview was analysed and presented according to the research question. The study results revealed that the majority of the teachers generally had a positive perception of authentic assessment. Again, it came to light from the study that there was no statistically significant difference between teachers’ academic qualifications and their perception of authentic assessment. The study, however, established that there was a statistically significant difference between teachers’ teaching experience and their perception of authentic assessment. It was recommended amongst others that periodic in-service training programs and workshops, organized by educational stakeholders in the Effutu Municipality, would foster a positive perception of authentic assessment among the teachers in the municipality.