This study was conducted during two successive seasons 2016 and 2017 on ten years old guava cv. Maamoura trees grown in private orchard located at Rasheed area, Beheira Governorate, Egypt.Guava trees grown at a distance of 4 x 4 m to study the effect of spraying moringa, seaweed extract and potassium on growth, yield and fruit quality of the winter guava Maamoura cultivar. The experiment was designed as randomized complete block design with five replicates. Each block contained 10 treatments as follow:control (spraying with water), foliar application of moringa leaf extract diluted to 10 times with water, foliar application of moringa leaf extract diluted to 20 times with water, foliar application of moringa leaf extract diluted to 30 times with water, foliar application of seaweed solution of a concentration at 1ml/ liter, foliar application of seaweed solution of a concentration at 2ml/ liter, foliar application of seaweed solution of a concentration at 3ml/ liter, foliar application of potassium K (1 %), foliar application of potassium K (2 %) and foliar application of potassium K (3 %). Results indicated that, moringa leaf extract diluted to 10 times with water gave the highest mean values of fruit set (%) and total soluble solid percentage, while, moringa leaf extract diluted to 10 times with water recorded the maximum  (%)  of fruit set and total soluble solid, also, foliar application of potassium K (3 %), gave the maximum values of fruit yield (kg/tree), yield (t/fed), fruit weight (g), fruit length (cm), fruit diameter(cm), fruit volume (cm³), plup weight (g), juice (%), acidity (%), total sugar (%), reducing sugar (%)  and non-reducing sugar (%)  as compared with the control which gave the lowest mean values of the characters.