Although much research on corporate dividend policy exists, the evidence is far from conclusive. Understanding how dividend taxes affect firm-level decisions is crucial to evaluating dividend imputation credits which provide shareholder-level tax credits for dividends received or decreased shareholder-level dividend tax rates, which reduce the double taxation of dividends. Using changes in New Zealand and Australia’s tax regimes, this dissertation provides new evidence on the relationship between tax incentives for R&D investment and dividend payment. The results show that the theory that the tension between R&D investment and dividend payment decreases when a country previously not offering tax incentives for R&D investment or dividend payout, implements one, does not hold using New Zealand firms. Further, New Zealand dividend-paying firms with higher marginal tax rates behave in the manner predicted for firms moving from a tax regime offering a tax incentive for R&D investment to a tax regime offering tax incentives for both R&D investment and dividend payment. The results using Australian data, demonstrate that that the tension between R&D investment and dividend payment increases when a country previously offering only a tax incentives for R&D investment, offers one for both R&D investment and dividend payment. This result is driven by firms with high marginal tax rates. These findings demonstrate that the relationship between tax incentives for R&D investment and dividend payment varies according to firm marginal tax rates and typical dividend payment policies. It also reiterates the importance of considering firms’ abilities to use R&D tax incentives, via their marginal tax rates, when contemplating the effects a shareholder-level dividend tax decrease will have on R&D investment. This dissertation also provides new insight into the corporate dividend policy views. The results support the double taxation and tax irrelevance views in dividend-paying firms operating in a tax regime with dividend imputation and capital gains taxes. By documenting a significant decrease in R&D investment after a change in dividend taxes, this dissertation also highlights a void in the current corporate dividend policy views and shows the need for the inclusion of R&D investment.