It had been suggested that Dejagah might play for Iran at the international level rather than Germany, but he said he never really considered it an option.
Having played for Germany at the age of 21, he was originally no longer eligible to play for Iran.
However, FIFA rule changes in July 2009 meant that he could play for Iran.
In late December, Iran's coach Afshin Ghotbi approached Dejagah about playing for Iran at the 2011 AFC Asian Cup in Qatar, but he declined because he wanted to focus on playing first team football with his club VfL Wolfsburg instead.

On 21 September 2011, he was invited to the Iranian national team by Carlos Queiroz.
He scored twice on his debut for Iran against Qatar on 29 February 2012 in a World Cup qualifier.
Upon qualification to the 2014 World Cup, his next international goals came on 15 and 19 November in Asian Cup qualifying wins over Thailand and Lebanon, sealing Iran's place in the 2015 Asian Cup as well.
Dejagah was named in Iran's 2014 FIFA World Cup squad by Carlos Queiroz.
He started for Iran in their opening match against Nigeria, but was substituted in the 73rd minute by Alireza Jahanbakhsh.
He also played 85 and 68 minutes in the next matches against Argentina and Bosnia and Herzegovina, respectively.
He was called into Iran's 2015 AFC Asian Cup squad on 30 December 2014 by Carlos Queiroz.

On 12 November 2015 after captain Andranik Teymourian was suspended, Dejagah captained the national team for the first time in his career and also scored in a 3–1 victory against Turkmenistan.

He was named in Iran's squad for the 2018 FIFA World Cup in Russia but did not feature in any matches as Iran was eliminated in the group stage.

On 26 December 2018, Dejagah was selected for Iranian squad for 2019 AFC Asian Cup.
He started Iran's first match of the tournament and scored the second goal in a 5–0 win Yemen.
It had been suggested that Dejagah might play for Iran at the international level rather than Germany, but he said he never really considered it an option. Having played for Germany at the age of 21, he was originally no longer eligible to play for Iran. However, FIFA rule changes in July 2009 meant that he could play for Iran. In late December, Iran's coach Afshin Ghotbi approached Dejagah about playing for Iran at the 2011 AFC Asian Cup in Qatar, but he declined because he wanted to focus on playing first team football with his club VfL Wolfsburg instead.
On 21 September 2011, he was invited to the Iranian national team by Carlos Queiroz. He scored twice on his debut for Iran against Qatar on 29 February 2012 in a World Cup qualifier. Upon qualification to the 2014 World Cup, his next international goals came on 15 and 19 November in Asian Cup qualifying wins over Thailand and Lebanon, sealing Iran's place in the 2015 Asian Cup as well. Dejagah was named in Iran's 2014 FIFA World Cup squad by Carlos Queiroz. He started for Iran in their opening match against Nigeria, but was substituted in the 73rd minute by Alireza Jahanbakhsh. He also played 85 and 68 minutes in the next matches against Argentina and Bosnia and Herzegovina, respectively. He was called into Iran's 2015 AFC Asian Cup squad on 30 December 2014 by Carlos Queiroz.
On 12 November 2015 after captain Andranik Teymourian was suspended, Dejagah captained the national team for the first time in his career and also scored in a 3–1 victory against Turkmenistan.
He was named in Iran's squad for the 2018 FIFA World Cup in Russia but did not feature in any matches as Iran was eliminated in the group stage.
On 26 December 2018, Dejagah was selected for Iranian squad for 2019 AFC Asian Cup. He started Iran's first match of the tournament and scored the second goal in a 5–0 win Yemen.
Ashkan Dejagah