Paginate entries ordered by a custom date field
Pulling it all inside paginate fixed it:

{% paginate craft.entries().section('events').limit(2).order('startDate asc') as events %}

{% for event in events %}
    // Event content
{% endfor %}

{% if paginate.prevUrl %}&lt;a href="{{ paginate.prevUrl }}"&gt;Previous Page&lt;/a&gt;{% endif %}
{% if paginate.nextUrl %}&lt;a href="{{ paginate.nextUrl }}"&gt;Next Page&lt;/a&gt;{% endif %}