The study investigated the effects of collaborative and portfolio writing strategies on students‟ performance in essay writing in senior secondary schools, Kaduna State, Nigeria. Seven objectives, research questions and hypotheses guided the study. The objectives were to: examine the effect of collaborative and conventional writing strategies, portfolio and conventional, collaborative, portfolio and conventional writing strategies on students‟ performance in essay writing: also, effect of collaborative, portfolio and conventional writing strategies on students‟ performance in content, organization and grammatical components of essay writing in senior secondary schools in Kaduna State. The study reviewed related literature. The target population of the study was forty nine thousand eight hundred SSII students from the 12 Educational Zones in Kaduna State. The sample size comprised of three hundred and seven SSII students from six intact classes. The study was carried out using quasi -experimental design. The instrument tagged „Essay Writing Performance Test" was used for data collection in the study. The instrument, after being validated by specialists in English Language and curriculum specialists was pilot-tested using a test and re-test method. The reliability index of 0.75 was gotten thereafter. Data for the study was collected through the administration of pre-test and post-test. The demographic data of the respondents were analyzed using descriptive statistics which involved frequencies and percentages while mean and standard deviation were used to analyze responses to research questions whilet-test and Analysis of Covariance were also used to test the hypotheses at 0.05 alpha level of significance.Findings from the study revealed that students taught essay writing using collaborative writing strategy performed significantly better than those taught using conventional writing strategy (p-value .000 <0.05); there was no significant difference in the performance of students taught essay writing using portfolio and conventional writing strategies ( p-value .587> 0.05); the performance of students taught essay writing using collaborative writing strategy was significantly better than those taught using portfolio writing strategy (p-value .000< 0.05); students taught essay writing using collaborative writing strategy had a significantly better performance than those taught using portfolio and conventional writing strategies (p-value .000< 0.05); and students taught essay writing using collaborative writing strategy performed significantly better in content, organization and grammatical components of their writing than those taught using portfolio and conventional writing strategies. Based on the findings, it was recommended among others that collaborative writing strategy should be adopted and promoted by teachers and stakeholders for teaching essay writing in senior secondary schools. Listening, reading and speaking skills can be enhanced using collaborative and portfolio writing strategies. Furthermore, collaborative writing strategy can be used to manage large essay writing classes.