The Scottish Secretary paid tribute to Sir Michael Fallon, who resigned as Defence Secretary after admitting his behaviour had ''fallen below the high standards required'' in the role.
Mr Mundell said he was confident that his own conduct met that required standard but added it was ultimately for his electors to judge.
He also backed a suggestion put forward by Scottish Conservative leader Ruth Davidson for a UK-wide code of conduct for elected officials and political staff.
He told reporters at Holyrood: "I don't see any reason, you know, when I put myself forward for election in June why I shouldn't do that but I always leave it to my electors to judge.
"I haven't got anything to declare but I leave it to electors to set out whether they believe you to be an appropriate person to be elected."
Asked if there were others who should consider their position, he added: "These are matters for them, people have to take their own decisions in the context of their own actions, their own lives."
"He's overseen the very, very important investment that's going ahead at Lossiemouth, at Faslane, at Leuchars, the frigates on the Clyde.
"He's been a great champion of Scotland's role in defence and the defence industry so as a colleague in that regard I will miss him, but Gavin Williamson who is taking over is a very accomplished individual with a very strong business background as well, so I'm confident in terms of the day to day operation of the Ministry of Defence that it will continue."
Asked whether the revelations about Sir Michael's conduct had come as a surprise, he said: "These things always have to be a personal decision, he obviously made that decision yesterday and that's a matter for him.
"In politics and other areas there are always stories swirling around all sorts of people.
"Social media has changed the dynamic in relation to a lot of those things and clearly that's a contribution to what is and isn't in the public domain and how it then impacts on people."
On the way forward Mr Mundell emphasised that while criminal behaviour should always be reported to the police "there has to be change" in the political world.
He said: "There has to be a much more professional human resources personnel system within parliament and political parties that people would expect in any modern forward-looking business environment where you can, if you've got concerns, report something to the person who isn't actually the alleged perpetrator or connected to them.
"We have to modernise, move forward in that. It's incumbent on all of us just to make absolutely clear that certain conduct is just not acceptable."
He said a UK wide code of conduct for politicians "certainly is worth looking at", adding: "I would like us to see a consistent approach so that people understand if they're going into public office what's expected of them and anyone who's working within that environment knows that conduct wouldn't be acceptable elsewhere, will not be acceptable in that environment and that there are processes and procedures that can do something about it."