Johanna Ernst (born 16 November 1992) is an Austrian professional rock climber who specialises in competition lead climbing, competition bouldering and outdoor sport climbing.
Ernst began climbing when she was 8 years old. Initially, she only competed in the competition lead climbing discipline. In 2008, when she was 16, she participated in her first Lead Climbing World Cup and won it, earning three gold, two silver and one bronze medals. In the same year she also won the Rock Master climbing festival and the Lead Climbing European Championship in Paris.
In 2009, she won the Lead Climbing World Championships in Qinghai and, for the second time in a row, the Lead Climbing World Cup. As a decoration of honor for these outstanding achievements, in 2009 she was also awarded the Gold Medal for Services to the Republic of Austria.
In 2010, she could not compete in the Lead Climbing World Cup due to an ankle sprain caused by a fall during the Bouldering World Cup on June 4 in Vail. She went on to earn a silver medal at the European Championships in Imst.