Literature on the effect of campaign spending by political parties mainly focuses on the US context. This thesis attempts to examine the effect of campaign spending by political parties on...Show moreLiterature on the effect of campaign spending by political parties mainly focuses on the US context. This thesis attempts to examine the effect of campaign spending by political parties on proportional systems in Western Europe, with a case study of the Netherlands. The Netherlands was chosen because of its proportional system and high electoral volatility and effective number of electoral parties compared to other Western European countries. This allows the effects of campaign spending to be more apparent relative to other Western European countries (Bekkouche et al., 2022; McAllister, 2002). This thesis focuses on campaign spending by Dutch political parties during national elections from 1998 to 2021. The results section indicates that higher campaign spending by political parties results in greater electoral gain compared to the polls two months before election day. Additionally, this thesis provides indications that campaign spending has a differentiated effect depending on the size of the party. However, it is important to interpret these findings with caution due to data collection limitations.Show less