The Scottish company confirmed it has agreed a deal with wi-fi provider The Cloud which will see all guests able to access the internet.
At some key conference and meeting venues, speeds of up to 100 megabytes per second are being offered, meaning services like video conferencing can be done wirelessly.
David Guile, chief executive at Macdonald Hotels & Resorts, said: "More and more guests see free, reliable internet access as a crucial part of their hotel visit, whether that's using social media to share holiday updates, business travellers who want to catch up on emails or access documents remotely or conference organisers who need to enable delegates full access to the internet as part of their training, presentation or workshop.
"To provide our guests with the service they expect we need to offer wi-fi that enables them to get online quickly and easily. This is a free, unlimited service, meaning people can spend as long as necessary online to ensure they get the most out of their stay."
Mr Guile said the investment was part of a wider programme of upgrades in back-office functions.