To investigate the relationship between motivation and cognitive strategies with special reference to the differences between Turkish and Iranian students of English (n=898), Deci and Ryan's (1985) self-determination theory, and Oxford's (1990) strategy inventory for language learning were adapted. The results showed Turkish and Iranian students were both intrinsically and extrinsically motivated. Iranian students' motivation level was more than Turkish students and Turkish students mostly used receiving and sending strategy, whereas Iranian students mostly used the cognitive strategy of creating structures for input and output. Motivation and four regulations in extrinsic motivation were positively correlated and there was an ordered pattern between motivation types and regulations. The more students were internally motivated the more they used cognitive strategies. Moreover, amotivation was negatively correlated to all types of cognitive strategies. In addition, there were significant gender differences within integrated regulation, external regulation, amotivation, and use of analyzing and reasoning strategy.