What is difference between diversity and deviance?

In general, the difference here (if we are talking about
sociology) is that diversity is used to refer to group characteristics while deviance is
used to refer to behaviors.  This is not 100% true, but it is the general difference
between the two.

Diversity tends to refer to things such as
differences of race, class, or culture.  These are things that typify a group.  These
sorts of differences do not have a moral value to them -- they are simply ways in which
people are different.  By contrast, deviance refers to behaviors that are seen by the
society as wrong.  This includes things such as crime, but it also includes behaviors
that are simply seen as immoral (though not
criminal).

There are some instances in which it is hard to
tell the two apart and in which classifying something as deviance or diversity is a
political or ideological issue.  The most obvious of these is homosexuality -- is this
something that is value neutral (diversity) or is it deviant?