Background: Gingival clefts (GC) develop frequently during orthodontic space closure and may compromise the treatment outcome. This study assessed whether the time-point of orthodontic space closure initiation, after permanent tooth extraction, affects the incidence of GC. Methods: In 25 patients requiring bilateral premolar extraction due to orthodontic reasons, one premolar, chosen at random, was extracted 8 weeks before space closure initiation (“delayed movement”, DM), while the contralateral premolar was extracted one week before (“early movement”, EM) (“treatment group”). Presence/absence of GC after 3 and 6 months (“time-point”) was recorded and any association with various parameters (i.e., treatment group, time-point, gender, jaw, craniofacial growth, gingival biotype, buccal bone dehiscence after extraction, space closure) was statistically assessed. Results: Twenty-one patients contributing with 26 jaws were finally included in the analysis. Overall, GC were frequent after 3 (DM: 53.9%; EM: 69.2%) and 6 months (DM: 76.9%; EM: 88.5%). EM (p=0.014) and larger space closure within the study period (p=0.001) resulted in a significantly higher incidence of GC. Further, there was a tendency for GC development in the presence of buccal bone dehiscence (p=0.052) and thin gingival biotype (p=0.054). “Fast movers” (herein cases with a tooth movement ≥ 1mm per month) developed a GC in > 90% of the cases already after 3 months. “Slow movers” developed a GC only in 25 and 70% after 3m and FE, respectively. Conclusions: GC development is a frequent finding during orthodontic space closure and seems to occur more frequently with early tooth movement initiation and in “fast movers”.