Self-regulated learning (SRL) strategies have gained a great prominence in second language reading comprehension; however, to have a comprehensive picture of their efficacy, this study investigated the significant relationships among SRL components, reading comprehension and reading problem solving. Moreover, it examined the effects of SRL instruction on SRL strategies, reading comprehension, problem solving and the strength of the relationships among these variables. To this end, 183 Iranian English as a foreign language (EFL) learners participated in two phases of this study. In the first phase, the pretest PLS-SEM models were analyzed by evaluating the Motivated Strategies for Learning Questionnaire, Solving Problem Scale, and a test of reading comprehension. The results indicated that from among the components of SRL, cognitive and metacognitive strategies were the dominant predictors of reading comprehension and problem solving, respectively. In the second phase, the effects of SRL instruction and the traditional instruction of reading comprehension on the strength of the relationships were investigated by performing multigroup analysis and comparing f[superscript 2] and R[superscript 2] values in the pretest-posttest models. The results indicated that SRL instruction was significantly efficient in improving EFL learners' SRL strategies, reading comprehension, and reading problem solving.