Aggressive ideations can be defined as thoughts, daydreams or fantasies of harming another. They feature intheoretical models of aggressive behaviour causation and are used in violence risk assessments. Little isknown, however, about long term relations between aggressive ideations, aggressive behaviour and relatedvariables such as self-control. We examined cross-lagged associations between these variables in the most recenttwo waves of the Zurich project on social development (z-proso) when the participants were aged 15 and 17. Wefound that aggressive ideations were highly stable across this time span. The only significant cross-lagged effectswere between aggressive behaviour at age 15 and self-control and aggressive ideations at age 17. Results are consis-tent with the strength model of self-control in which changes in specific self-controlled behaviour can producegeneralised changes in self-control. They are also consistent with the hypothesis that aggressive ideations aremore a reaction to or a reflection of shared causes with, rather than a cause of, aggressive behaviour. Future studiesshould aim to integrate measurements across short and long time scales in order to further understand the causalinteractions between aggressive ideations and behaviours as they play out across at the state and trait level.