Approximately 10 to 12% of GHG emissions come from the agricultural sector. Consumption of energy in agriculture is a source of GHG and it can be decreased by efficient utilization of energy inputs. Therefore, our present research calculated energy efficiencies (for technical, pure technical, and scale) and extent of GHG reduction after benchmarking an inefficient farm in off-season cucumber production in Punjab, Pakistan. Primary data were collected from 70 farmers with simple random sampling. Average technical efficiency (TE), pure technical efficiency (PTE), and scale efficiency (SE) were 0.77, 0.91, and 0.85, respectively, while increasing (IRS) and constant (CRS) return to scale were observed in 46 and 24 farms, respectively. The decrease in total input energy was 33,908.00 MJ ha^-1 (14.14%) if inefficient farmers use the energy inputs according to recommendations. A large share of energy savings comes from fertilizers (63.66%), followed by diesel (25.88%), plastic (5.78%), chemicals (2.69%), water (1.06%), labour (0.50%), and machinery (0.44%). Total GHG reduction was 1,004.68 kg CO₂ eq.ha^-1 (17.75%) after improvement in energy efficiency. Agricultural extension staff should visit the vegetable farms on a regular basis and give necessary information about efficient utilization of energy inputs. In addition, the government should promote renewable sources of energy due to their environmentally friendly behavior.