The Somalia-born four-time Olympic champion could be affected by the ban, which prevents those from Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen entering the US for 90 days or more.
There are concerns the policy could affect UK citizens born abroad and Sir Mo is worried President Trump’s decree could keep him apart from his family.
In a statement, Sir Mo, who lives and trains in the US, said: “On 1st January this year, Her Majesty The Queen made me a Knight of the Realm. On 27th January, President Donald Trump seems to have made me an alien.
“I am a British citizen who has lived in America for the past six years - working hard, contributing to society, paying my taxes and bringing up our four children in the place they now call home.
“Now, me and many others like me are being told that we may not be welcome.
“It’s deeply troubling that I will have to tell my children that daddy might not be able to come home - to explain why the president has introduced a policy that comes from a place of ignorance and prejudice.
“I was welcomed into Britain from Somalia at eight years old and given the chance to succeed and realise my dreams.
“I have been proud to represent my country, win medals for the British people and receive the greatest honour of a knighthood.
“My story is an example of what can happen when you follow polices of compassion and understanding, not hate and isolation.”
Sir Mo trains in Portland, Oregon, where he lives with his wife Tania and their four children.
He moved to the UK from Somalia - one of the proscribed countries - when he was eight, becoming a British citizen. A British passport holder, he does not have dual nationality or hold a Somalian passport.
Sir Mo is currently training in Ethiopia and his team are unsure how and if he will be affected by the travel ban.
A representative said: “We are seeking to clarify the situation with the US authorities. Mo is currently at a training camp and is not planned to return to the US for a number of weeks.
“However, as I’m sure you can appreciate, he and Tania want to understand the direct impact on them (if any) as a matter of urgency.”