The Scotch Whisky Association (SWA) said the "uncertain global economy and political uncertainty" has created challenges for whisky exporters.
However, SWA chief executive David Frost said: "Scotch whisky exports continue to deliver and the fundamentals for future growth are strong.
"Whilst the last couple of years have been more difficult, the longer-term picture has been one of increased demand, new investment, and premiumisation.”
Exports reached £3.86bn in customs value in 2015, down 2.4% on last year, but the decline has slowed from the 7% fall seen in 2014.
Total export value is now 56% higher than a decade ago and the SWA said prospects for growth remain strong.
The volume of Scotch exports was down by 2.8% last year to 1.16 billion bottles (from 1.19 billion). That represented 34 bottles of whisky every second being shipped from Scotland.
Consumer demand for single malt continues to be strong, with shipments up to £916.4m in 2015 (from £914m).
Single malts now account for nearly 25% of the value Scotch whisky exports in 2015, up from 18% five years ago.
Blends remain the biggest category (£2.77bn), accounting for 72% of the global value of exports.
The US, the biggest export destination for Scotch, remained steady at £749m, nearly a fifth of all exports, and exports to Japan were up 18% to £76m.
There was also growth in a number of emerging markets, with Mexico up 17% to £115m, Turkey up 24% to almost £53m and China returning to the top 20 markets with an increase of 5% to £41m.