In a blog post late Monday, Bing's Duane Forrester said users had an option to use encryption for the past year and a half, but that this will be the default option by mid-year.
Bing joins Google and Yahoo, which have been making encryption standard as part of an effort to thwart snooping, amid heightened concerns since the leak of documents in 2013 by former US intelligence contractor Edward Snowden.
"Microsoft has a long history and deep commitment to helping protect our customers' data and the security of their systems," Forrester said.
"While this change may impact marketers and webmasters, we believe that providing a more secure search experience for our users is important."
Microsoft in mid-May said its Bing search engine would be reconfigured to give more prominence to "mobile-friendly" websites, an acknowledgment of the growing importance of smartphones and other mobile devices.
The announcement came just weeks after Google implemented a similar shift. The moves by the two search engines could have big implications for website operators, advertisers and for those who seek to optimise search rankings.
"Based on data from user's interaction with Bing, we have seen that mobile users are able to satisfy their information needs much faster on searches that return more mobile-friendly results," Microsoft's Shyam Jayasankar had said in a blog post. "With that in mind, we will be rolling out mobile friendliness as a signal in ranking."
Written with inputs from AFP