More than 28,000 homes and 450 business premises in Scotland have installed solar photo-voltaic (PV) systems, December figures from regulator Ofgem show.
The capacity of these systems has reached 106 megawatts, up from just 2 megawatts in 2010 and an increase of 36% on the same time last year.
The organisations want the Scottish Government to do as much as it can to support people to go solar.
WWF Scotland director Lang Banks said: "The total may be small when compared to wind energy, but reaching 100 megawatts of installed solar capacity still represents a significant milestone on Scotland's path toward generating only pollution-free electricity.
"Alongside energy saving measures, renewable energy technologies like solar and wind will be important to enabling Scotland meet its climate change targets."
A typical home solar PV system could save more than a tonne of carbon dioxide per year, according to the Energy Savings Trust.
Dr Anne-Marie Fuller, chairwoman of the Scottish Solar Energy Group, said: "Scotland might seem like an unlikely place for solar, but if you look at a solar radiation map, Scotland receives about 80%, and in some parts 90%, of the solar energy of Germany, the world leader in solar deployment with about 35 gigawatts installed to date.
Dr Fuller, who is also solar business development executive for the Energy Technology Partnership, said it is an extremely versatile electricity generation technology.