Viktor Röthlin (born October 14, 1974 in Kerns, Obwalden) is a Swiss former long-distance runner, who specialized in the marathon.

[1] Röthlin has set four Swiss national records at the marathon distance: In September 2001 at the Berlin Marathon, his time of 2:10:54 eclipsed the previous Swiss national record of 2:11:10 (set by Daniel Boltz in 1991).

In April 2004, in his victory at the Zürich Marathon, Röthlin lowered the national record to 2:09:56.

Röthlin attempted no marathons in 2009, because he contracted thrombosis during a flight from the United Arab Emirates in the Spring of 2009, which led to a pulmonary embolism and fluid buildup in his chest; the condition was treated with rest and medication.

[3] Röthlin retired from competitive marathon running in 2014, after finishing fifth at the European Championships in Zürich.