This paper introduces the emerging field of practice theory as it is applied to organizational phenomena. It identifies three approaches—empirical, theoretical, and philosophical—that address the "what," "how," and "why" of using a practice lens. The paper discusses three principles of the theoretical approach to practice and provides examples of how practice theory has been used in organizational research. It concludes with a discussion of the challenges and opportunities that practice theory offers to organizational scholarship. Practice theory is a broad intellectual landscape with recognizable features. It emphasizes the relationship between situated actions and the social world, the rejection of dualisms, and the relationality of mutual constitution. These principles are central to understanding how practices shape social reality. Practice theory is particularly well-suited to analyzing complex, dynamic, distributed, mobile, and unprecedented organizational phenomena. The paper presents three applications of practice theory in organizational studies: strategy, knowledge, and neoinstitutionalism. In strategy, scholars use practice theory to understand the relational and enacted nature of strategizing. In knowledge, scholars use practice theory to reformulate notions of knowledge as consequential activity grounded in everyday situated practice. In neoinstitutionalism, scholars use practice theory to inform their theorizing of institutional maintenance and change. The paper also presents two personal stories of using practice theory in organizational research. Martha's story discusses her study of organizational routines, where she found that routines are not static but dynamic, with internal (endogenous) dynamics that produce both stability and change. Wanda's story discusses her study of technology in the workplace, where she found that technology is not valuable by itself but becomes so when people engage with it in practice. She argues that technology in practice is constituted through recurrent interactions with technologies and that the specific technologies in practice (enacted technology structures) are consequential for organizational outcomes. The paper concludes by emphasizing the value of practice theory for organizational scholarship, particularly in understanding the complex, dynamic, and unpredictable nature of organizational phenomena. It highlights the importance of a practice lens in analyzing the interplay between human agency and structural conditions, and in understanding the role of materiality in the production of social life.This paper introduces the emerging field of practice theory as it is applied to organizational phenomena. It identifies three approaches—empirical, theoretical, and philosophical—that address the "what," "how," and "why" of using a practice lens. The paper discusses three principles of the theoretical approach to practice and provides examples of how practice theory has been used in organizational research. It concludes with a discussion of the challenges and opportunities that practice theory offers to organizational scholarship. Practice theory is a broad intellectual landscape with recognizable features. It emphasizes the relationship between situated actions and the social world, the rejection of dualisms, and the relationality of mutual constitution. These principles are central to understanding how practices shape social reality. Practice theory is particularly well-suited to analyzing complex, dynamic, distributed, mobile, and unprecedented organizational phenomena. The paper presents three applications of practice theory in organizational studies: strategy, knowledge, and neoinstitutionalism. In strategy, scholars use practice theory to understand the relational and enacted nature of strategizing. In knowledge, scholars use practice theory to reformulate notions of knowledge as consequential activity grounded in everyday situated practice. In neoinstitutionalism, scholars use practice theory to inform their theorizing of institutional maintenance and change. The paper also presents two personal stories of using practice theory in organizational research. Martha's story discusses her study of organizational routines, where she found that routines are not static but dynamic, with internal (endogenous) dynamics that produce both stability and change. Wanda's story discusses her study of technology in the workplace, where she found that technology is not valuable by itself but becomes so when people engage with it in practice. She argues that technology in practice is constituted through recurrent interactions with technologies and that the specific technologies in practice (enacted technology structures) are consequential for organizational outcomes. The paper concludes by emphasizing the value of practice theory for organizational scholarship, particularly in understanding the complex, dynamic, and unpredictable nature of organizational phenomena. It highlights the importance of a practice lens in analyzing the interplay between human agency and structural conditions, and in understanding the role of materiality in the production of social life.