1. Log into your account and view your account settings by clicking on the silhouette of a person, located in the top right hand corner. Select Settings.
2. Select Apps in the left hand menu.
3. Any applications that can access your account will be displayed. The level of access is listed below each application name (such as read/write, direct messaging etc). Click on Revoke access for any applications that you don’t use or don’t trust.
4. If you suspect your account has been compromised it is always advisable to change your password immediately. Do this by clicking on the Password tab.
If you have given access to your Twitter account through an IOS device (iPad, iPhone or iPod) then you will need to revoke the app's access from your IOS device. Select the Settings app on your device.
Select the Twitter tab in Settings, then scroll down to see the linked apps. Set the button to OFF to unlink the app.