The purpose of this essay is to seek knowledge and a better understanding on how the EU and it´s member states´ security policy reform against terrorism after 9/11 has been effective or not, and to examine whether there are any clear differences between the strategies of the selected member states. The chosen member states in the EU are Belgium, Sweden and the United Kingdom. The questions are: 1. Are there any differences and/or similarities in the security policy reform after 9/11 between Belgium, Sweden and the United Kingdom? 2. What is the effectiveness of the above-mentioned countries security policy reform in the fight against terrorism? 

The study aims to be a qualitative and comparative design. The chosen method of the study is a combination of Most Similar System Design and Most Different System Design. The collected information in the empirical chapter is limited to strategies, laws and statistics on terrorism in Belgium, Sweden an the United Kingdom in the period after 9/11, thus from year 2001 to year 2020. The theory which the study is based on is efficiency and effectiveness. 

The conclusions are that there are more similarities than differences between the selected EU-member states in their counter-terrorism after 9/11. They have similar strategies and similar legislations, the big difference is that the UK has a more extensive and strict legislation than Belgium and Sweden has. The chosen EU-member states have some flaws in the prevention of radicalization on individuals who are traveling abroad to fight in different terrorist organizations like ISIS and Al-Qaida. That needs to be worked on further to get a better efficiency and effectiveness. Belgium, Sweden and the UK have a efficiency and effectiveness when it comes to adapt their strategies to the purpose and new challenges that comes from jihadist terrorism. The statistics shows that the number of terrorist attacks has been reduced in Belgium, but the number of dead people has increased since the arabic spring. This suggests that the efficiency and effectiveness in preventing attacks to occur is high, but Belgium need to use another strategy in protecting it´s citizens. The statistics says that the number of terrorist attacks in the UK has increased since 9/11, but also shows that the UK are preventing more than half of the attacks in 2019. This suggests that the efficiency and effectiveness is good, but the strategy needs to be worked on further.