This study explores the key issues, aspects, and attributes concerning capital gains tax (CGT) to enable the formulation of policy guidelines that might be used if a CGT were considered in New Zealand. It contends that the development of the New Zealand’s policy on taxing capital gains has continued in a somewhat ad hoc and inconsistent fashion. The lack of a uniform approach to capital gains taxation has resulted in detailed, but complex, legislation which leads to “policy inconsistencies and unintended incentives built into the tax structure” (Oliver, 2001, pp. 80 – 81). The study bridges the divide between theoretical analysis of CGT and implementation issues on operating a CGT. It attempts to address one primary research question and an associated secondary question. The primary research question is: should capital gains be taxed more comprehensively than at present? As a start, it examines the two important issues surrounding income definition and the capital/income distinction. In this regard, the research first attempts to identify the definition(s) of capital gains from the New Zealand perspective(s). This is followed by investigating the key areas of the tax system in order to seek the best way of taxing capital gains. This study also attempts to address the secondary research question, i.e., why (or why not) do the tax experts favour (or oppose) a comprehensive CGT? In this respect, this study identifies 23 factors/issues that are related to the tax experts’ attitudes towards a particular form of a CGT model (i.e., current hybrid approach, a realisation-based CGT or an accrual-based CGT). A mixed-methods design has been adopted in this study involving both a quantitative (survey) and a qualitative (interview) method in analysing the data to determine the tax experts’ overall perceptions of a CGT in New Zealand and the CGT adoption factors which influenced them. One important finding of the comparative analyses was that all tax experts generally agreed that the lack of a comprehensive CGT could provide more significant tax planning opportunities. However, many tax experts did not support the comprehensive income concept as they disagreed with the benefits derived from the gains in horizontal equity through adopting a CGT. This study has identified several important policy issues and reviewed their implication for the adoption of a CGT in New Zealand. The finding of the study revealed that the tax experts strongly supported the exemption of the gains on disposal of a taxpayer’s main residence and the tax preference for inflation adjustment. Another important policy issue is the implementation of an accrual-based CGT. Most tax experts considered a realisation-based CGT would be better than an accrual one. In particular, they were concerned about the liquidity problems and the compliance costs involved in an accrual-based CGT regime i.e., the annual valuation of all assets. These findings represent a first step towards a theoretical CGT framework. It is hoped that the knowledge gained in this study would give a greater understanding into the practical decision-making process that could result in a better public acceptance for a tax reform.