To thrive in the turbulent modern economy, businesses across industries are looking to maximize the versatility and performance of employees and management. In many cases, developing an agile and high performing workforce may be critical to organizations that seek to gain competitive advantages and grow into new markets. Organizations are increasingly investing in understanding and optimizing their employees through many human resource (HR) management strategies, also referred to as High-Performance Work Systems (HPWS). Researchers have tied specific human resource (HR) interventions to gains in individual employee performance and other related outcomes. Due to rapid globalization, it is important to assess the cross-cultural generalizability of effects associated with the implementation of HPWS in multinational firms. Thus, this thesis investigated HPWS and organizational performance outcomes across nations. This research can expand our understanding of HPWS practices in multinational organizations. Archival data from the sixth European Company Survey (ECS) were used. The ECS examined the implementation of HPWS practices in European countries to gain a better understanding of the most effective workplace practices. The dataset includes management representatives from 30,000 companies and employee representatives from 9,000 companies in 32 countries. Countries’ sample sizes ranged from 280 to 1514 Survey items were grouped according to five HPWS dimensions; these dimensions included training, process improvement, pay, meetings, and communication. Organizational performance was grouped into four areas: operational & financial performance, work climate, industrial action, and staffing & retention management. Multilevel regression analyses were used to evaluate the relationship between HPWS practices and firm-level organizational performance outcomes. Nation-level embeddedness, intellectual autonomy, affective autonomy, hierarchy, egalitarianism, and mastery were investigated as moderators of these effects, using cross-level analyses. As expected, this study generally found that HPWS and organizational performance are positively related. These effects were generally stronger for cultures that are higher in embeddedness and mastery, and lower in autonomy. Overall, this study suggests that companies seeking to increase their organization’s performance should consider implementing HPWS practices. Additionally, HPWS practices yield greater returns when cultures emphasize identification with groups and other important collectives of which employees are members, and when cultures emphasize mastery and less autonomy.