TreeView is a user-friendly phylogenetic tree viewing utility designed for personal computers, compatible with both MacOS and Microsoft Windows. It supports standard fonts, printers, and graphics formats, and allows users to utilize the graphical interface features of their operating systems. TreeView can read and display trees in various styles, including edge lengths and internal node labels, and supports file operations like drag-and-drop. It can handle multiple tree files and save trees in different formats. The program is available for download from the World Wide Web site and is compatible with both Macintosh and Windows operating systems. The author acknowledges contributions from several users and researchers who helped in the development and testing of the program.TreeView is a user-friendly phylogenetic tree viewing utility designed for personal computers, compatible with both MacOS and Microsoft Windows. It supports standard fonts, printers, and graphics formats, and allows users to utilize the graphical interface features of their operating systems. TreeView can read and display trees in various styles, including edge lengths and internal node labels, and supports file operations like drag-and-drop. It can handle multiple tree files and save trees in different formats. The program is available for download from the World Wide Web site and is compatible with both Macintosh and Windows operating systems. The author acknowledges contributions from several users and researchers who helped in the development and testing of the program.