Reporting a high level of meaning in one’s life has been found to impact an individual’s wellbeing and mental health in a positive way. However, the majority of meaning-orientated interventions have been developed to help individuals cope with adversity, while limited interventions have focused on promoting, flourishing, and preventing mental illnesses in the general population. This research aimed to develop and test an online meaning in life intervention aimed at the general population. Based on a theoretical framework of meaning in life and empirically validated approaches, a convenience sample of Icelandic adults (N = 177) participated in a Randomised Control Trial (RCT) and were assigned to one of two interventions or an active control group. The hypothesis stated that a Motivational Meaning Intervention and Cognitive Motivational Meaning Intervention would result in greater perceptions of self-reported Meaning in Life, Subjective Wellbeing, Psychological Wellbeing and Positive Affect compared to a control condition. The results showed that both interventions enhanced positive affect while neither intervention increased meaning in life, subjective wellbeing nor psychological wellbeing. The interventions appear to be inexpensive, easily administered, and effective in increasing positive affect which is a major contributor to an individual’s wellbeing. The study offers meaningful conclusions and future avenues to enhance intervention studies to develop essential elements of wellbeing and human functioning within general populations.