Johannes Monrad Aagaard (29 April 1928 – 23 March 2007) was a Danish theologian and evangelist. He was a professor of missiology at the University of Aarhus and was active in the Christian countercult movement as the founder of the Dialog Center International, an international educational organization concerned with groups it defines as cults and other new religious movements.
Aagaard had travelled to Asia and was concerned about Buddhism and other Eastern religions, which he felt were gaining influence in Europe. In 1973 Aagaard founded the Dialog Center which was later greatly influential in promoting a negative public opinion of cults in Denmark and other European nations. He regarded Scientology as being especially dangerous, but later in his life stated that Islam was an even greater threat. Other concerns included Satanism and New Age groups. Aagaard cooperated with both religious and secular anti-cultists, but opposed deprogramming of cult members since he felt that it was ineffective and often counterproductive. He retired from the Dialog Center in 2002.